TY - JOUR A1 - Peplinski, Burkhard A1 - Adamczyk, Burkart A1 - Formanek, P. A1 - Meyer, Christian A1 - Krüger, O. A1 - Scharf, Holger A1 - Reinsch, Stefan A1 - Ostermann, Markus A1 - Nofz, Marianne A1 - Jäger, Christian A1 - Adam, Christian A1 - Emmerling, Franziska T1 - Nanocrystalline and stacking-disordered beta-cristobalite AlPO4 chemically stabilized at room temperature: synthesis, physical characterization, and X-ray powder diffraction data N2 - This paper reports the first successful synthesis and the structural characterization of nanocrystalline and stacking-disordered β-cristobalite AlPO4 that is chemically stabilized down to room temperature and free of crystalline impurity phases. Several batches of the title compound were synthesized and thoroughly characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy, selected area electron diffraction, energy dispersive X-ray spectroscopy mapping in SEM, solid-state 31P nuclear magnetic resonance (31P-NMR) spectroscopy including the TRAPDOR method, differential thermal analysis (DTA), gas-sorption methods, optical Emission spectroscopy, X-ray fluorescence spectroscopy, and ion chromatography. Parameters that are critical for the synthesis were identified and optimized. The synthesis procedure yields reproducible results and is well documented. A high-quality XRD pattern of the title compound is presented, which was collected with monochromatic copper radiation at room temperature in a wide 2θ range of 5°–100°. KW - Stabilization of high-temperature phase at RT KW - Nanochrystalline AlPO4 KW - Beta-christobalite structure type KW - High-cristobalite form KW - Aluminium phosphate PY - 2017 DO - https://doi.org/10.1017/S0885715617000537 SN - 1945-7413 SN - 0885-7156 VL - 32 IS - S1 SP - S193 EP - S200 PB - JCPDS-ICDD CY - Cambridge AN - OPUS4-42235 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Huber, Alexandra A1 - Behnke, Thomas A1 - Würth, Christian A1 - Jäger, Christian A1 - Resch-Genger, Ute T1 - Spectroscopic characterization of coumarin-stained beads: quantification of the number of fluorophores per particle with solid-state 19F-NMR and measurement of absolute fluorescence quantum yields N2 - The rational design of nano- and micrometer-sized particles with tailor-made optical properties for biological, diagnostic, and photonic applications requires tools to characterize the signal-relevant properties of these typically scattering bead suspensions. This includes methods for the preferably nondestructive quantification of the number of fluorophores per particle and the measurement of absolute fluorescence quantum yields and absorption coefficients of suspensions of fluorescent beads for material performance optimization and comparison. Here, as a first proof-of-concept, we present the first time determination of the number of dye molecules per bead using nondestructive quantitative (19F) NMR spectroscopy and 1000 nm-sized carboxylated polystyrene particles loaded with varying concentrations of the laser dye coumarin 153 containing a CF3 group. Additionally, the signal-relevant optical properties of these dye-loaded particles were determined in aqueous suspension in comparison to the free dye in solvents of different polarity with a custom-built integrating sphere setup that enables spectrally resolved measurements of emission, transmission, and reflectance as well absolute fluorescence quantum yields. These measurements present an important step toward absolute brightness values and quantitative fluorescence analysis with particle systems that can be exploited, for example, for optical imaging techniques and different fluorescence assays as well as for the metrological traceability of fluorescence methods. PY - 2012 DO - https://doi.org/10.1021/ac3000682 SN - 0003-2700 SN - 1520-6882 VL - 84 IS - 8 SP - 3654 EP - 3661 PB - American Chemical Society CY - Washington, DC AN - OPUS4-25873 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hennig, Andreas A1 - Borcherding, H. A1 - Jäger, Christian A1 - Hatami, Soheil A1 - Würth, Christian A1 - Hoffmann, Angelika A1 - Hoffmann, Katrin A1 - Thiele, T. A1 - Schedler, U. A1 - Resch-Genger, Ute T1 - Scope and limitations of surface functional quantification methods: exploratory study with poly(acrylic acid)-grafted micro- and nanoparticles N2 - The amount of grafted poly(acrylic acid) on poly(methyl methacrylate) micro- and nanoparticles was quantified by conductometry, 13C solid-state NMR, fluorophore labeling, a supramolecular assay based on high-affinity binding of cucurbit[7]uril, and two colorimetric assays based on toluidine blue and nickel complexation by pyrocatechol violet. The methods were thoroughly validated and compared with respect to reproducibility, sensitivity, and ease of use. The results demonstrate that only a small but constant fraction of the surface functional groups is accessible to covalent surface derivatization independently of the total number of surface functional groups, and different contributing factors are discussed that determine the number of probe molecules which can be bound to the polymer surface. The fluorophore labeling approach was modified to exclude artifacts due to fluorescence quenching, but absolute quantum yield measurements still indicate a major uncertainty in routine fluorescence-based surface group quantifications, which is directly relevant for biochemical assays and medical diagnostics. Comparison with results from protein labeling with streptavidin suggests a porous network of poly(acrylic acid) chains on the particle surface, which allows diffusion of small molecules (cutoff between 1.6 and 6.5 nm) into the network. KW - Polymers KW - Surface groups KW - Quantification KW - Fluorescence PY - 2012 DO - https://doi.org/10.1021/ja302649g SN - 0002-7863 SN - 1520-5126 VL - 134 IS - 19 SP - 8268 EP - 8276 PB - American Chemical Society CY - Washington, DC AN - OPUS4-26002 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Elimination of Artifacts in NMR Spectroscopy made "EASY" T2 - 15th Brasilian Magnetic Resonance Conference AUREMN 15 CY - Angra dos Reis, Brasilien DA - 2015-06-08 PY - 2015 AN - OPUS4-34308 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - What is the NMR group at the BAM - Federal Institute of Materials Research and Testing doing: On purity assessments of small molecules and solid state chemistry (from organics to inorganics) T2 - IPT - Instituto de Pesquisas Tecnológicas CY - Sao Paulo, Brasilien DA - 2015-06-17 PY - 2015 AN - OPUS4-34309 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hemmann, Felix A1 - Agirrezabal-Telleria, Iker A1 - Kemnitz, E. A1 - Jäger, Christian T1 - Probing slow chemical exchange of pyridine molecules at acid magnesium hydroxide fluoride surfaces by 15N NMR N2 - 15N NMR of pyridine has been used to study Lewis and Brønsted sites at the acid surface of magnesium hydroxide fluoride at two different pyridine loadings with ratios of excess pyridine compared to pyridine molecules bound to Lewis and Brønsted sites of about 1:1 (highly loaded) and 0.15:1 (low loaded), respectively. The Lewis and Brønsted sites can be distinguished by the 15N chemical shift of pyridine at about –100 ppm (LPy) and –175 ppm (BPy). In both samples a very broad 15N resonance is found around –88 ppm assigned to weakly adsorbed (excess) pyridine molecules via hydrogen bridges (HPy). Additionally, another signal at about –49 ppm is observed in the highly loaded sample only representing physisorbed pyridine (PPy). A slow chemical exchange process of strongly bound LPy and BPy molecules with excess HPy and PPy molecules can be monitored using 15N exchange NMR. It takes place on a time scale of about 50–100 ms at room temperature. All pyridine molecules have the same 15N T1 and its value increases from 800 ms (highly loaded sample) to 5.3 s (low loading) hinting on changed pyridine mobility depending on the loading level. KW - Catalysis KW - Acid surfaces KW - 15N NMR KW - Chemical exchange KW - Pyridine PY - 2014 DO - https://doi.org/10.1021/jp405213x SN - 1932-7447 SN - 1089-5639 VL - 117 IS - 28 SP - 14710 EP - 14716 PB - Soc. CY - Washington, DC AN - OPUS4-30439 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jeromenok, J. A1 - Böhlmann, W. A1 - Jäger, Christian A1 - Weber, J. T1 - Carbon dioxide adsorption in Betulin-based micro- and macroporous polyurethanes N2 - Separation of CO2. Microporous polyurethane networks were prepared based on a renewable resource. Betulin, extracted from birch bark, is used as a structure-directing diol monomer in A3-B2 monomers. The resulting microporous networks show very promising CO2/N2 selectivities. The state of adsorbed CO2 is analyzed by in situ NMR spectroscopy, and pure physisorption is proven. The preparation of monolithic materials is demonstrated as well. KW - Carbon dioxide KW - Gas adsorption KW - Microporous polymers KW - Renewable resources KW - Solid state NMR spectroscopy PY - 2013 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-304431 DO - https://doi.org/10.1002/open.201200045 SN - 2191-1363 VL - 2 IS - 1 SP - 17 EP - 20 PB - Wiley-VCH-Verl. CY - Weinheim AN - OPUS4-30443 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Agirrezabal-Telleria, Iker A1 - Hemmann, Felix A1 - Jäger, Christian A1 - Arias, P. L. A1 - Kemnitz, E. T1 - Functionalized partially hydroxylated MgF2 as catalysts for the dehydration of d-xylose to furfural N2 - Among the furan-based compounds, furfural (FUR) shows interesting properties as building-block or industrial solvent. It is produced from pentosan-rich biomass via xylose cyclodehydration. The current FUR production uses homogeneous catalysts and steam. According to recent studies, the reaction mechanism is different in the presence of Lewis (L) or Brønsted (B) sites. In this work, partially hydroxylated MgF2 catalysts, containing bifunctional Lewis and Brønsted properties, were further functionalized using different fluorosulfonic precursors. Its main objective was to test these solids as catalysts for xylose conversion to furfural. Extensive characterization techniques using TG–MS, 19F-MAS-NMR, or pyridine adsorption confirmed the substitution of surface OH groups by stronger Brønsted sites. The activity data showed a considerable change of the reaction kinetics and a final furfural selectivity of 90% at 160 °C in water/toluene for optimized L/B ratios by the one-step grafting technique. Moreover, the reaction analyses and the change of conversion pathways were studied. KW - Hydroxylated MgF2 KW - Functionalization KW - Fluorosulfonic acid KW - Lewis KW - Brønsted KW - Xylose KW - Furfural PY - 2013 DO - https://doi.org/10.1016/j.jcat.2013.05.005 VL - 305 SP - 81 EP - 91 AN - OPUS4-30444 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hieu, D.T. A1 - Kosslick, H. A1 - Riaz, M. A1 - Schulz, A. A1 - Springer, A. A1 - Frank, M. A1 - Jäger, Christian A1 - Minh Thu, N.T. A1 - Son, L.T. T1 - Acidity and Stability of Bronsted Acid Sites in Green Clinoptilolite Catalysts and Catalytic Performance in the Etherification of Glycerol N2 - Natural zeolite clinoptilolite CLIN with a framework ratio of Si/Al ≥ 4 containing mainly potassium and calcium ions in its internal channel system was used as a starting material. The acidic HCLIN catalysts were prepared under soft conditions avoiding the use of environmental less benign mineral acids. The starting material was ion exchanged using a 0.2 M aqueous ammonium nitrate solution at a temperature 80 ◦C for 2 h. The obtained NH4CLIN was converted into the acid HCLIN catalyst by calcination at 300–600 ◦C. The obtained samples were characterized by XRD, FTIR, SEM/TEM, AAS, and EDX element mapping. The state of aluminium and silicon was studied by 27Al- and 29SiMAS NMR spectroscopy. The textural properties of the catalysts were investigated by nitrogen adsorption and desorption measurements. The Brønsted acidity of the HCLIN catalysts was studied by temperature-programmed decomposition of the exchanged ammonium ions releasing ammonia as well as 1H MAS NMR, {1H–27Al} Trapdor, and {1H–27Al} Redor experiments. The strongly agglomerated samples were crystalline and thermally stable up to >500 ◦C. Although a part of the clinoptilolite framework is maintained up to 600 ◦C, a loss of crystallinity is already observed starting from 450 ◦C. The specific surface areas of the starting CLIN and ammonium exchanged NH4CLIN are low with ca. 26 m2/g. The pores are nearly blocked by the exchangeable cations located in the zeolite pores. The thermal decomposition of the ammonium ions by calcination at 400 ◦C causes an opening of the pore entrances and a markable increase in the specific micropore area and micropore volume to ca. 163 m2/g and 0.07 cm3/g, respectively. It decreases with further rising calcination temperature indicating some structural loss. The catalysts show a broad distribution of Brønsted acid sites (BS) ranging from weak to strong sites as indicated the thermal decomposition of exchanged ammonium ions (TPDA). The ammonium ion decomposition leaving BS, i.e., H+ located at Al–O–Si framework bridges, starts at ≥250 ◦C. A part of the Brønsted sites is lost after calcination specifically at 500 ◦C. It is related to the formation of penta-coordinated aluminium at the expense of tetrahedral framework aluminium. The Brønsted sites are partially recreated after repeated ammonium ion exchange. The catalytic performance of the acidic HCLIN catalysts was tested in the etherification of glycerol as a green renewable resource with different C1 -C4 alcohols. The catalysts are highly active in the etherification of glycerol, especially with alcohols containing the branched, tertiary alkyl groups. Highest activity is observed with the soft activated catalyst HCLIN300 (300 ◦C, temperature holding time: 1 min). A total of 78% conversion of glycerol to mono and di ether were achieved with tert-butanol at 140 ◦C after 4 h of reaction. The mono- and di-ether selectivity were 75% and 25%, respectively. The catalyst can be reused. KW - Etherification KW - Glycerol KW - Zeolite KW - Clinoptilolite KW - Bronsted acidity KW - Dehydroxylation PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546982 DO - https://doi.org/10.3390/catal12030253 VL - 12 IS - 3 SP - 1 EP - 24 PB - MDPI AN - OPUS4-54698 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wanner, C. A1 - Poethig, R. A1 - Carrero, S. A1 - Fernandez-Martinez, A. A1 - Jäger, Christian A1 - Furrer, G. T1 - Natural occurrence of nanocrystalline Al-hydroxysulfates: Insights on formation, Al solubility control and As retention N2 - Nanocrystalline basaluminite [Al4OH10(SO4)(H2O)3–5] and Aggregation of the e-Keggin polyoxocation [Al12(AlO4)(OH)24(H2O)12]7+, referred to as Al13, have both been described to form in acid mine Drainage environments. Although the chemical composition is quite similar, their crystalline varieties significantly differ, demonstrating that various types of Al-hydroxysulfates can form under similar conditions and that their respective formation is not fully understood yet. Here, we report the occurrence of nanocrystalline precipitates that form naturally in a small alpine catchment in Switzerland where an acidic mountainous stream (pH 4) is neutralized successively after mixing with several neutral tributaries. The stepwise neutralization in conjunction with the large amount of precipitates provide an ideal setting for obtaining new insights into (i) the structure of naturally forming Al-hydroxysulfates, (ii) their formation mechanism, (iii) their role in controlling the solubility of Al, and (iv) their ability to lower the mobility of As. Synchrotron-based high-energy X-ray diffraction and subsequent pair distribution function analyses demonstrate that these precipitates are structurally identical to basaluminite samples obtained from acid mine drainage sites. In contrast, only minor amounts of tetrahedrally coordinated Al, as present in Al13, were identified by nuclear magnetic resonance spectroscopy. The precipitates are further characterized by elevated As concentrations up to 600 lg/g, whereas other heavy metals are at background concentrations only. Given the low As concentrations in the stream from which precipitation occurs (<0.03 mg/L), high As concentrations confirm that basaluminite serves as a highly efficient As sink, which is attributed to its high anion-exchange capacity. Chemical analysis of streamwater samples in combination with geochemical modeling show that precipitation occurs instantaneously upon mixing with neutral streams. Moreover, our data reveal that the precipitation of basaluminite exerts a strong solubility control on dissolved Al concentrations as manifested by the quasi-constant basaluminite ion activity product observed during neutralization from pH 5 to pH 5.9. We hypothesize that in our field system, high fluoride and sulfate concentrations on the order of 100 and 1–2 mg/L, KW - Basaluminite KW - Al13 KW - Acid rock drainage KW - Arsenic retention KW - Aluminum KW - Anion exchange PY - 2018 DO - https://doi.org/10.1016/j.gca.2018.06.031 SN - 0016-7037 SN - 1872-9533 VL - 238 SP - 252 EP - 269 PB - Elsevier Ltd. AN - OPUS4-46164 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jäger, Christian A1 - Hemmann, Felix T1 - EASY: A simple tool for simultaneously removing background, deadtime and acoustic ringing in quantitative NMR spectroscopy. Part II: Improved ringing suppression, application to quadrupolar nuclei, cross polarisation and 2D NMR N2 - A simple experiment for Elimination of Artifacts in NMR SpectroscopY (EASY) was introduced in Part I, and it was shown that NMR probe background signals, spectral distortions due to deadtime effects, and acoustic ringing can be eliminated simultaneously from solid-state NMR spectra. In this Part II, it is shown that acoustic ringing suppression can be improved up to one order of magnitude compared to the original EASY pulse sequence by inserting a delay τ between the two data acquisition scans of the EASY pulse sequence. The achievable ringing suppression depends on the length of this delay and is limited by the spin-lattice relaxation time T1. Furthermore, EASY is considered in conjunction with NMR of quadrupolar nuclei. For strong second-order broadening, EASY can be used to acquire either pure central transition MAS patterns or pure satellite transition NMR spectra. Two further modifications to EASY are introduced. One concerns improved ringing artifact suppression in experiments in which the central transition NMR signal is amplified by Rotor Assisted Population Transfer (RAPT). The second EASY modification enables the acquisition of quantitative NMR spectra if signals with different quadrupole coupling constants are present. In addition, acoustic ringing and 11B stator signals are removed. Finally, it is demonstrated that the basic idea of EASY for removing ringing artifacts can be realized for heteronuclear one-dimensional and hetero- and homo-nuclear multi-dimensional NMR experiments using extended phase cycling. 15N{1H} CPMAS and 15N 2D Exchange NMR spectroscopy are considered as examples. KW - Solid State NMR KW - Probe background suppression KW - Ringing suppression KW - Deadtime KW - qNMR of quadrupolar nuclei KW - CPMAS NMR KW - 2D NMR KW - 11B KW - 23Na KW - 25Mg PY - 2014 DO - https://doi.org/10.1016/j.ssnmr.2014.08.001 SN - 0926-2040 SN - 1527-3326 VL - 63-64 SP - 13 EP - 19 PB - Academ. Press CY - Orlando, Fla. AN - OPUS4-32329 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jäger, Christian A1 - Hemmann, Felix T1 - EASY: A simple tool for simultaneously removing background, deadtime and acoustic ringing in quantitative NMR spectroscopy-Part I: Basic principle and applications N2 - Elimination of Artifacts in NMR SpectroscopY (EASY) is a simple but very effective tool to remove simultaneously any real NMR probe background signal, any spectral distortions due to deadtime ringdown effects and -specifically- severe acoustic ringing artifacts in NMR spectra of low-gamma nuclei. EASY enables and maintains quantitative NMR (qNMR) as only a single pulse (preferably 90°) is used for data acquisition. After the acquisition of the first scan (it contains the wanted NMR signal and the background/deadtime/ringing artifacts) the same experiment is repeated immediately afterwards before the T1 waiting delay. This second scan contains only the background/deadtime/ringing parts. Hence, the simple difference of both yields clean NMR line shapes free of artefacts. In this Part I various examples for complete 1H, 11B, 13C, 19F probe background removal due to construction parts of the NMR probes are presented. Furthermore, 25Mg EASY of Mg(OH)2 is presented and this example shows how extremely strong acoustic ringing can be suppressed (more than a factor of 200) such that phase and baseline correction for spectra acquired with a single pulse is no longer a problem. EASY is also a step towards deadtime-free data acquisition as these effects are also canceled completely. EASY can be combined with any other NMR experiment, including 2D NMR, if baseline distortions are a big problem. KW - Solid state NMR KW - MAS KW - Probe background suppression KW - Ringing suppression KW - Deadtime KW - 1H KW - 19F KW - 11B KW - 13C KW - 25Mg PY - 2014 DO - https://doi.org/10.1016/j.ssnmr.2013.11.002 SN - 0926-2040 SN - 1527-3326 VL - 57-58 SP - 22 EP - 28 PB - Academ. Press CY - Orlando, Fla. AN - OPUS4-29839 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bücker, Michael A1 - Jäger, Christian A1 - Pfeifer, Dietmar A1 - Unger, Brita T1 - Evidence of Si-O-C bonds in cellulosic materials modified by sol-gel-derived silica N2 - The present study contributes to the controversial discussion in the literature whether Si–O–C bonds in wood–silica–gel composites exist. 13C NMR is a suitable method to proof such bonds. Because of the low concentration of 13C isotopes in natural wood, 13C cellulose was used as 13C-enriched substitute. A tailored sol for the impregnation of that cellulose was chosen by liquid 29Si NMR pre-investigations of various sols whose reactivity and stability were time-dependently analysed. It is based on a sub-stoichiometric hydrolysis of tetraethoxysilane (TEOS) with 1 mol water per mol TEOS. Thermal analyses were performed to show a comparability of the thermal behaviour of wood–silica–gel and cellulose–silica–gel composites. There are two strong hints of the existence of stable Si–O–C bonds: (1) by thermal analysis, a shift in the fire behaviour of 100 K can be observed with a change in pyrolysis behaviour of the composite and (2) the proof by REDOR NMR that a dipolar coupling between 1329Si and 13C nuclei exists. KW - Silica-cellulosic composites KW - Sol-gel derived silica KW - Si-O-C bonds KW - 13C NMR KW - 29Si NMR PY - 2014 UR - http://link.springer.com/article/10.1007/s00226-014-0657-9/fulltext.html DO - https://doi.org/10.1007/s00226-014-0657-9 SN - 0043-7719 SN - 1432-5225 VL - 48 IS - 5 SP - 1033 EP - 1047 PB - Springer CY - Berlin AN - OPUS4-31223 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Patrick A1 - Morys, Michael A1 - Sut, Aleksandra A1 - Jäger, Christian A1 - Illerhaus, Bernhard A1 - Schartel, Bernhard T1 - Melamine poly(zinc phosphate) as flame retardant in epoxy resin: Decomposition pathways, molecular mechanisms and morphology of fire residues N2 - Synergistic multicomponent systems containing melamine poly(metal phosphate)s have been recently proposed as flame retardants. This work focuses on the decomposition pathways, molecular mechanisms and morphology of the fire residues of epoxy resin (EP) flame retarded with melamine poly(zinc phosphate) (MPZnP) to explain the modes of action and synergistic effects with selected synergists (melamine polyphosphate (MPP) and AlO(OH), respectively). The total load of flame retardants was always 20 wt.%. The decomposition pathways were investigated in detail via thermogravimetric Analysis coupled with Fourier transform infrared spectroscopy. The fire residues were investigated via elemental analysis und solid-state nuclear magnetic resonance spectroscopy. The morphology of intumescent fire residues was investigated via micro-computed tomography and scanning electron microscopy. EP + (MPZnP + MPP) formed a highly voluminous residue that showed structural features of both EP + MPZnP and EP + MPP, resulting in a highly effective protection layer. EP + (MPZnP + AlO(OH)) preserved the entire quantity of phosphorus content during combustion due to the Formation of Zn₂P₂O₇ and AlPO₄. KW - Melamine poly(metal phosphate) KW - Flame retardancy KW - Epoxy resin KW - Solid-state NMR KW - Micro-computed tomography KW - Fire residue PY - 2016 DO - https://doi.org/10.1016/j.polymdegradstab.2016.06.023 SN - 0141-3910 VL - 130 SP - 307 EP - 319 PB - Elsevier AN - OPUS4-36863 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meißner, G. A1 - Dirican, D. A1 - Jäger, Christian A1 - Braun, T. A1 - Kemnitz, E. T1 - Et3GeH versus Et3SiH: controlling reaction pathways in catalytic C–F bond activations at a nanoscopic aluminum chlorofluoride† N2 - Catalytic C–F bond activation reactions of mono- and polyfluoroalkanes at Lewis acidic amorphous aluminum chlorofluoride (ACF) are presented. The hydrogen sources Et3GeH or Et3SiH control the selectivity of the conversions. The immobilization of Et3GeH at ACF resulted in catalytic dehydrohalogenation reactions to yield olefins under very mild conditions. In contrast, if Et3SiH is immobilized at ACF, C–C coupling occured and the formation of Friedel–Crafts products was observed. MAS NMR spectroscopic studies revealed information about the surface binding of the substrates. KW - Vapor-phase hydrofluorination KW - Carbon-fluorine bonds KW - Vinyl fluoride KW - Phosphine-ligands KW - Room-temperature KW - Building-blocks KW - Etal-complexes KW - Germylium ions KW - Lewis-acids KW - Hydrodefluorination PY - 2017 DO - https://doi.org/10.1039/c7cy00845g SN - 2044-4753 SN - 2044-4761 VL - 7 IS - 15 SP - 3348 EP - 3354 PB - The Royal Society of Chemistry AN - OPUS4-41836 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Barheine, Sabrina A1 - Hayakawa, S. A1 - Osaka, A. A1 - Jäger, Christian T1 - Surface, interface, and bulk structure of borate containing apatitic biomaterials N2 - Nuclear magnetic resonance (NMR) has been used for a detailed investigation of the borate incorporation in apatitic biomaterials prepared by high-temperature solid-state reaction sintering. The NMR data clearly show that crystalline hydroxyapatite (HAp) does exist, but it contains only about 30% of the entire phosphate content of the sample. The main phosphate content of about 70% forms a disordered calcium phosphate phase (BCaP) that accommodates the borate units in two structurally different trigonal BO33- groups besides some minor linear BO2- units. The average chemical composition of BCaP was estimated from the NMR spectra. Furthermore, a structural model of these particles is proposed, where HAp forms the crystalline core of these crystals covered by the disordered BCaP, suggesting that the BCaP phase is responsible for the adhesion properties of organic molecules like proteins and not HAp that is the only significant crystalline phase (XRD). Furthermore, the presence of an interface between HAp and BCaP is discussed based on various NMR experiments, including a triple-resonant 11B-31P cross-polarization edited 31P NMR spectrum with subsequent 31P{1H} REDOR (Rotational Echo DOuble Resonance) dephasing. PY - 2009 DO - https://doi.org/10.1021/cm900204q SN - 0897-4756 SN - 1520-5002 VL - 21 IS - 14 SP - 3102 EP - 3109 PB - American Chemical Society CY - Washington, DC AN - OPUS4-19723 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Thermal Decomposition of Flame-Retarded Polycarbonat / Silicon Rubber Blends: A Solid-State NMR Investigation T2 - Festkörper-NMR-Methoden und Anwendungen in der Materialforschung, Seminar der Universität Tübingen CY - Bad Hindelang, Germany DA - 2010-07-18 PY - 2010 AN - OPUS4-21679 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Thermal Decomposition of Flame-Retarded Polycarbonat / Silicon Rubber Blends: A Solid-State NMR Investigation T2 - 52. Rocky Mountain Conference on Analytical Chemistry CY - Snowmass, CO, USA DA - 2010-08-01 PY - 2010 AN - OPUS4-21680 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - 31P MAS NMR - a Method for Analysis ans Development of Complex Bioceramics based on Ca 10(K,Na)(PO 4)7 T2 - 52nd Anual Rocky Mountain Conference on Analytical Chemistry CY - Snowmass, CO, USA DA - 2010-08-01 PY - 2010 AN - OPUS4-21702 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Barheine, Sabrina A1 - Jäger, Christian T1 - A NMR investigation of borate incorpation in apatitic biomaterials T2 - Gesellschaft Deutscher Chemiker CY - Regensburg, Germany DA - 2008-09-22 PY - 2008 AN - OPUS4-17966 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koudelka, L. A1 - Mosner, P. A1 - Zeyer-Düsterer, Michaela A1 - Jäger, Christian ED - Brooks, H. T1 - Study of potassium-zinc borophosphate glasses N2 - Potassium–zinc borophosphate glasses were prepared and studied in two compositional series xK2O–(50–x)ZnO–10B2O3–40P2O5 and xK2O–(50–x)ZnO–20B2O3–30P2O5 with x = 0, 10, 20, 30, 40 and 50 mol% K2O. The replacement of zinc by potassium decreases the density and increases the molar volume of these glasses, whereas glass transition temperature and chemical durability decrease with increasing potassium content. Structural changes were studied by 11B and 31P MAS NMR and Raman spectroscopy. The observed changes in the spectra and the properties of the studied glasses can be ascribed to several reasons and namely to the differences in the space occupied by cations Zn2+ and 2K+, the differences in the electronegativity of zinc and potassium and a large difference in the field strength of Zn2+ and K+ cations and thus higher ionicity of K–O bonds in comparison with Zn–O bonds. KW - A. Glasses KW - C. Raman spectroscopy KW - D. Nuclear magnetic resonance PY - 2007 DO - https://doi.org/10.1016/j.jpcs.2007.02.012 SN - 0022-3697 VL - 68 IS - 4 SP - 638 EP - 644 PB - Pergamon Press CY - New York, NY AN - OPUS4-17579 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maltsev, Sergey A1 - Duer, M.J. A1 - Murray, R.C. A1 - Jäger, Christian T1 - A solid-state NMR comparison of the mineral structure in bone from diseases joints in the horse N2 - In this work, subchondral cortical bone material is investigated from the joints of five horses, three of which presented with no clinical signs or radiographic signs of osteoarthritis and two of which suffered osteoarthritis joint disease, as judged by clinical and radiographic assessment and histological findings. The horse is a good model for osteoarthritis in humans, so the aim of this study is to use nuclear magnetic resonance (NMR) for a detailed investigation of the bone structure in bone material affected by osteoarthritis. In particular, we report on the assessment of the mineral structure of these samples as viewed by solid-state NMR. KW - Bone KW - Osteoarthritis KW - NMR PY - 2007 DO - https://doi.org/10.1007/s10853-007-1916-z SN - 0022-2461 SN - 1573-4803 VL - 42 IS - 21 SP - 8804 EP - 8810 PB - Springer Science + Business Media B.V. CY - Norwell, Mass. AN - OPUS4-17580 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Fichera, M.A. A1 - Jäger, Christian A1 - Schartel, Bernhard A1 - Braun, Ulrike A1 - Pawlowski, Kristin ED - Menachem Lewin, T1 - Solid-state NMR for monitoring the thermal decomposition of flame retarded polymers PY - 2007 SN - 1-59623-321-4 VL - I SP - 9 EP - 19 PB - BCC Research CY - Norwalk, CT, USA AN - OPUS4-17581 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jäger, Christian A1 - Cölfen, H. T1 - Fine structure of nacre revealed by solid state 13C and 1H NMR N2 - Solid-state NMR investigations of nacre reveal the presence of an amorphous surface layer around the aragonite platelets. This surface layer contains hydrogen carbonate groups, presumably at its outer surface and water molecules slightly hindered in their mobility in a proton ratio of 1:33, i.e. about 16 water molecules per HCO3– unit. The 1H spin–lattice relaxation T1 times of protons in the protein/polysaccharide matrix (about 300 ms), of the mobile water molecules (2 s) and of the hydrogen carbonate units (12 s) differ significantly, thus revealing no spatial proximity between the protein/polysaccharide matrix with the hydrogen carbonate units of the amorphous carbonate surface layer suggesting no significant interaction between protein matrix and the amorphous calcium carbonate (ACC) layer. These results are discussed in the context of recent publications on novel structural aspects of nacre. KW - NMR KW - Nacre KW - Amorphous carbonate layer KW - Protein interaction PY - 2007 DO - https://doi.org/10.1039/b708600h SN - 1466-8033 VL - 9 SP - 1237 EP - 1244 CY - London, UK AN - OPUS4-17582 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wise, Erica R. A1 - Maltsev, Sergey A1 - Davies, M.E. A1 - Duer, M.J. A1 - Jäger, Christian A1 - Loveridge, N. A1 - Murray, Rachel C. A1 - Reid, D.G. T1 - The Organic - Mineral Interface in Bone Is Predominantly Polysaccharide KW - NMR KW - Bone KW - Mineral-organic interface PY - 2007 DO - https://doi.org/10.1021/cm702054c SN - 0897-4756 SN - 1520-5002 VL - 19 IS - 21 SP - 5055 EP - 5057 PB - American Chemical Society CY - Washington, DC AN - OPUS4-17583 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hayakawa, S. A1 - Sakai, A. A1 - Tsuru, K. A1 - Osaka, A. A1 - Fujii, E. A1 - Kawabata, K. A1 - Jäger, Christian T1 - Preparation and Characterization of Boron-containing Hydroxyapatite N2 - Boron-containing hydroxyapatite (BHAp) particles were synthesized by the wet chemical processing method and subsequent thermal treatment at the temperature ranging from 700-1200°C, and examined the effect of boron introduction on the microstructure of BHAp. The local structure around boron and phosphorus in the BHAp was analyzed by solid-state magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. The heat-treatment above 700°C induced the thermal decomposition of HAp to β-TCP and then the chemical reaction between HAp and B(OH)3 was induced above 900°C, resulting in the formation of boron-substituted HAp particles accompanied by the formation of β-TCP and its transformation to α-TCP above 1200°C. KW - Hydroxyapatite KW - Boron KW - Structure KW - NMR KW - Thermal treatment PY - 2008 SN - 1013-9826 VL - 361-363 SP - 191 EP - 194 PB - Trans Tech Publ. CY - Aedermannsdorf AN - OPUS4-17584 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karrasch, Andrea A1 - Jäger, Christian A1 - Karakawa, M. A1 - Nakatsubo, F. A1 - Potthast, A. A1 - Rosenau, T. T1 - Solid-state NMR studies of methyl celluloses. Part 1: regioselectively substituted celluloses as standards for establishing an NMR data basis N2 - Three methyl celluloses with completely uniform substitution pattern, 2-O-methyl cellulose (1), 3-O-methyl cellulose (2) and 6-O-methyl cellulose (3), were prepared according to the cationic ring opening polymerization approaches starting from substituted 1,2,4-orthopivalate derivatives of D-glucose. These samples allowed for the first time to sort out the methyl substitution effects on solid-state NMR chemical shifts and relaxation. Dipolar dephasing experiments allowed the detection and assignment (1H, 13C) of the methyl groups. In 1 and 2, these resonances overlapped with those of C-6, whereas in 3, the methyl signal experienced a low-field shift into the region of C-2,3,5. 13C T1 experiments were used to verify different relaxation behavior of the carbon sites, particularly the short relaxation time of at the carbon substitution site next to the methyl groups. This effect was used to unambiguously identify the 13C chemical shifts of the carbons carrying the methoxyl substituent, although they overlap with all resonances in the C-2,3,5 region. The data obtained for the standard samples with uniform substitution will now be used as the basis for determining methylation patterns and substitution degree in commercial methyl celluloses. KW - Methyl cellulose KW - Solid-state NMR KW - CPMAS NMR KW - Substituent distribution KW - Substitution pattern KW - Cationic ring opening polymerization KW - Methylation PY - 2009 DO - https://doi.org/10.1007/s10570-008-9247-z SN - 0969-0239 SN - 1572-882X VL - 16 SP - 129 EP - 137 PB - Chapman & Hall CY - London AN - OPUS4-18913 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Barheine, Sabrina A1 - Hayakawa, S. A1 - Osaka, A. A1 - Jäger, Christian T1 - A NMR investigation of borate incorporation in apatitic biomaterials N2 - The incorporation of ions in the lattice of hydroxyapatite alters significantly its structure. Particularly, if anions such as trigonal borate units are accommodated in the lattice severe distortions must occur around the substitution site because of different geometric shape, electric charge and anion size. Solid-state NMR has been used to investigate this problem in detail for a hydroxyapatite sample synthesized by high temperature solid state reaction. The results clearly verify the existence of network distortions. Indeed, only about 1/3 of the total phosphate content forms crystalline hydroxyapatite (also found in XRD) whereas the residual amount is contained in two different phosphate sites with 31P chemical shifts of 5.5 ppm and 2.3 ppm, but broad resonances lines suggesting disorder. Furthermore, a novel proton signal at -0.6 ppm was found which is directly associated with the borate incorporation. No specific correlation of the two structurally different borate units with the two phosphate groups is found. KW - Apatite KW - Borate KW - Biomaterials KW - Solid-state NMR PY - 2009 UR - http://www.scientific.net/0-87849-353-0/205/ DO - https://doi.org/10.4028/3-908453-07-0.205 SN - 1013-9826 VL - 396-398 SP - 205 EP - 208 PB - Trans Tech Publ. CY - Aedermannsdorf AN - OPUS4-18914 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yoneda, Y. A1 - Mereiter, K. A1 - Jäger, Christian A1 - Brecker, L. A1 - Kosma, P. A1 - Rosenau, T. A1 - French, A. T1 - Van der Waals versus Hydrogen-Bonding Forces in a Crystalline Analog of Cellotetraose: Cyclohexyl 4'-O-Cyclohexyl Beta-D-Cellobioside Cyclohexane Solvate KW - Cellobioside KW - Cellotetraose KW - Cellulose KW - Solid state NMR PY - 2008 DO - https://doi.org/10.1021/ja805147t SN - 0002-7863 SN - 1520-5126 VL - 130 SP - 16678 EP - 16690 PB - American Chemical Society CY - Washington, DC AN - OPUS4-18915 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - NMR beyond limits: Surfaces of phosphate nanoparticles and interface in biomaterials T2 - Universität Mainz CY - Mainz, Germany DA - 2007-12-17 PY - 2007 AN - OPUS4-19189 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karrasch, Andrea A1 - Jäger, Christian A1 - Saake, B. A1 - Potthast, A. A1 - Rosenau, T. T1 - Solid-state NMR studies of methyl celluloses. Part 2: Determination of degree of substitution and O-6 vs. O-2/O-3 substituent distribution in commercial methyl cellulose samples N2 - Solid state NMR spectroscopy was applied to determine the overall degree of substitution (DS) and the degrees of substitution at C-6 (DSC-6) and C-2/3 (DSC-2/3). Four commercial methyl cellulose samples were used, having a DS between 0.51 and 1.96 as determined by wet-chemical analysis. The strategy and optimization of the NMR data acquisition as well as the data evaluation procedures are explained in detail. Optimization of the approach mainly comprised (a) maximizing the signal by choice of NMR probe, MAS spinning frequency and B0 field, (b) minimizing the measurement time by a Torchia-type experiment and (c) suppressing probe background by rotor-synchronized echo detection. Data evaluation used simply the integration of three different spectral ranges in the 13C NMR spectrum. The results of the experiments were in good agreement with the wet-chemical data. The NMR approach takes about the same analysis time as the conventional hydrolysis/chromatography analysis. However, it is a generally applicable and simple alternative without need for an extended sample preparation which is most useful if wet-chemical/chromatographic analyses are undesired or unavailable. Further studies have to concentrate on the validation of the analytical method and application to a larger sample array. KW - Methyl cellulose KW - Solid-state NMR KW - 13C CPMAS NMR KW - Rotor-synchronized echo sequence KW - Substituent distribution KW - Substitution pattern KW - Degree of substitution PY - 2009 DO - https://doi.org/10.1007/s10570-009-9304-2 SN - 0969-0239 SN - 1572-882X VL - 16 IS - 6 SP - 1159 EP - 1166 PB - Chapman & Hall CY - London AN - OPUS4-21130 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lutz, W. A1 - Kurzhals, R. A1 - Sauerbeck, S. A1 - Toufar, H. A1 - Buhl, J.-C. A1 - Gesing, T. A1 - Altenburg, Wolfgang A1 - Jäger, Christian T1 - Hydrothermal stability of zeolite SAPO-11 N2 - The hydrothermal stability of SAPO-11 was studied in water of autogenous pressure as function of the temperature. SAPO-11 remained crystalline up to 190 °C. Thereby, it was observed, parent as well as hydrothermally treated samples showed similarities to the isotypic structure of zeolite AlPO-11 called here AELdry. After fully hydration of the samples, AELdry changed completely into a hydrated AELwet structure of another framework symmetry. The transition from calcined to hydrated state was reversible for both the parent and the hydrothermally treated samples. 27Al and 31P NMR MAS spectra showed a single resonance typical for AlPO4 type tetrahedra for the calcined parent and hydrothermally treated samples. Upon hydration, the single AlPO4 resonance signal split into three different signals as is the case for the corresponding 31P signals. By means of NH3-TPD measurement a loss of acidity was detected after the hydrothermal treatment as follows from a framework desilication. Nitrogen and water adsorption decreased systematically. At 210 °C a non-zeolitic, non-porous phase was irreversibly formed. The XRD pattern of this phase shows resemblance to a synthetic aluminium phosphate of the tridymite structure type. KW - Zeolite KW - Silicoaluminophosphate KW - SAPO-11 KW - Hydrothermal stability KW - Phase transformation PY - 2010 DO - https://doi.org/10.1016/j.micromeso.2009.08.003 SN - 1387-1811 SN - 1873-3093 VL - 132 IS - 1-2 SP - 31 EP - 36 PB - Elsevier CY - Amsterdam AN - OPUS4-21131 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Debatin, F. A1 - Thomas, A. A1 - Kelling, A. A1 - Hedin, N. A1 - Bacsik, Z. A1 - Senkovska, I. A1 - Kaskel, S. A1 - Junginger, M. A1 - Müller, H. A1 - Schilde, U. A1 - Jäger, Christian A1 - Friedrich, A. A1 - Holdt, H.-J. T1 - In situ synthesis of an imidazolate-4-amide-5-imidate ligand and formation of a microporous zinc-organic framework with H2-and CO2-storage ability KW - Metal-organic framework KW - Synthesis KW - XRD KW - FTIR KW - NMR KW - Gas sorption KW - Microporous materials KW - N,O ligands KW - Solvothermal synthesis PY - 2010 DO - https://doi.org/10.1002/anie.200906188 SN - 1433-7851 SN - 1521-3773 SN - 0570-0833 VL - 49 IS - 7 SP - 1258 EP - 1262 PB - Wiley-VCH CY - Weinheim AN - OPUS4-21132 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scholz, G. A1 - Krahl, Thoralf A1 - Ahrens, M. A1 - Martineau, C. A1 - Buzaré, J.Y. A1 - Jäger, Christian A1 - Kemnitz, E. T1 - 115In and 19F MAS NMR study of (NH4)3InF6 phases N2 - This study presents for the first time an NMR spectroscopic characterization of the room and high temperature phases of (NH4)3InF6 using 19F and 115In as probe nuclei. The reversible phase transition to the cubic phase at 353 K was followed by MAS NMR in situ. Static NMR experiments of the room temperature phase and MAS NMR experiments of the high temperature phase allowed the determination of the NMR parameters of both nuclei. Finally, the scalar In–F coupling, rarely observed in solid state NMR, is evidenced in both room and high temperature phases of (NH4)3InF6, and measured in the high temperature phase. KW - (NH4)3InF6 KW - 115In and 19F solid state NMR KW - XRD PY - 2011 DO - https://doi.org/10.1016/j.jfluchem.2011.01.010 SN - 0022-1139 SN - 1873-3328 VL - 132 IS - 4 SP - 244 EP - 249 PB - Elsevier CY - Amsterdam AN - OPUS4-23475 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dreßler, Martin A1 - Nofz, Marianne A1 - Pauli, Jutta A1 - Jäger, Christian T1 - Influence of polyvinylpyrrolidone (PVP) on alumina sols prepared by a modified Yoldas procedure N2 - Al13 polycations containing alumina sols, prepared by a modified Yoldas procedure were mixed with polyvinylpyrrolidone (PVP). Although Al speciation in freshly prepared sols was not affected by PVP addition the decay rate of Al13 polycations was slightly decreased in PVP-containing sols. PVP does not show any influence on particle size and particle growth. The influence of PVP addition on viscosity and flow behavior of modified Yoldas sols depends on their solids content and NO3-/Al molar ratio. KW - ModifiedYoldas sols KW - PVP KW - NMR KW - Rheology KW - Particle size KW - Aging PY - 2008 DO - https://doi.org/10.1007/s10971-008-1798-9 SN - 0928-0707 SN - 1573-4846 VL - 47 IS - 3 SP - 260 EP - 267 PB - Kluwer Academic Publ. CY - Dordrecht AN - OPUS4-17854 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Karrasch, Andrea A1 - Jäger, Christian T1 - Thermal decomposition of PDMS in flame-retarded bisphenol-A polycarbonate: A solid-state NMR investigation T2 - GDCh-Tagung Magnetische Resonanz 2008 CY - Regensburg, Germany DA - 2008-09-22 PY - 2008 AN - OPUS4-17831 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Bulk and surfaces of nanosized calcium phosphates and their interaction with organic molecules in bone and synthetic biomaterials T2 - The 6th International Symposium on Inorganic Phosphate Materials (ISIPM-6- La Rochelle 2008) CY - La Rochelle, France DA - 2008-08-24 PY - 2008 AN - OPUS4-17883 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian A1 - Barheine, Sabrina T1 - A NMR investigation of borate incorpation in apatitic biomaterials T2 - 21st International Symposium of Ceramics in Medicine - Bioceramics 21 CY - Búzios, Brazil DA - 2008-10-21 PY - 2008 AN - OPUS4-17884 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Mission Impossible? Surfaces of phosphate nanoparticles and the mineral-organic interface in biomaterials T2 - Max-Planck-Institut für Chemische Physik Fester Stoffe CY - Dresden, Germany DA - 2008-05-09 PY - 2008 AN - OPUS4-17885 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Mission Impossible? Surfaces of phosphate nanoparticles and the mineral-organic interface in biomaterials T2 - Seminar "Festkörper-NMR-Methoden und Anwendungen in der Materialforschung", Universität Tübingen CY - Bad Hindelang, Germany DA - 2008-07-13 PY - 2008 AN - OPUS4-17886 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Aguiar, H. A1 - Solla, E.L. A1 - Serra, J. A1 - González, P. A1 - León, B. A1 - Malz, Frank A1 - Jäger, Christian T1 - Raman and NMR study of bioactive Na2O-MgO-CaO-P2O5-SiO2 glasses N2 - The results of a structural study combining NMR and Raman spectroscopy of several melt-derived glasses in the system Na2O–MgO–CaO–P2O5–SiO2 are presented. The Raman spectra show clear changes in the Si–O–Si vibrational modes (related to the bridging oxygen atoms, BO) and also verify the presence of non-bridging oxygen atoms (NBO), also named terminal oxygens. The intensity of the Si–O–NBO stretching mode depends on the cation concentration. It can be concluded from the NMR studies that the MgO-containing samples have orthophosphate units charge-compensated by Ca2+ and Mg2+. The silicate matrix also contains both types of two-valent cations and consists of Q2 and Q1 units. Similarly, the Na2O-containing samples contain isolated orthophosphate units in a silicate matrix (Q2 and Q3 units), both charge-compensated by mixed cations Ca2+ and Na+. These experimental data were compared with theoretical parameters given by the Stevels model, which is a suitable tool for understanding bioactive behavior of these glasses. Furthermore, results of the in vitro tests carried out in simulated body fluids are presented and compared with both Raman and NMR structural data. KW - Raman KW - NMR KW - Solid state KW - Bioactive glasses KW - Glass ceramics PY - 2008 DO - https://doi.org/10.1016/j.jnoncrysol.2008.07.033 SN - 0022-3093 VL - 354 IS - 45-46 SP - 5004 EP - 5008 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-18364 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - König, R. A1 - Scholz, G. A1 - Pawlik, Alf A1 - Jäger, Christian A1 - van Rossumm, B. A1 - Oschkinat, H. A1 - Kemnitz, E. T1 - Crystalline Aluminium Hydroxy Fluorides: Structural Insights Obtained by High Field Solid State NMR and Trend Analyses N2 - A series of crystalline aluminum hydroxy fluorides in cubic pyrochlore structure AlFx(OH)3-x·H2O with variable F-content x were investigated by solid-state NMR by applying different magnetic fields up to 21.1 T. Distinguishable octahedral species AlFx(OH)6-x (x = 1-6) were identified in the crystalline aluminum hydroxy fluorides. The subsequent analysis of the highfield 27Al MAS NMR data allows the derivation of the trend analysis graphs giving correlations between the 27Al chemical shifts and the quadrupolar frequencies and the F-content x in AlFx(OH)6-x. Clear trends were obtained for both, which are, along with the 19F MAS chemical-shift trend analysis presented earlier, valuable tools for the interpretation of MAS NMR spectra of amorphous AlFx(OX)3-x compounds (X = H, alkyl). Following the dehydration of the pyrochlores by solid-state NMR eventually reveals a remarkable influence of the incorporated solvent molecules (H2O) on the 19F chemical shift. On that basis, a new chemical-shift trend analysis for 19F chemical shifts in correlation with x in AlFx(OH)6-x units for proton-poor substances (in the Al, F, O, H system) was determined. By using this correlation, high-surface AlF3 has a mean bulk Al:F ratio similar to that found for ACF, namely, AlF2.8(O/OH)0.2. KW - Aluminium-27 KW - Crystalline aluminium hydroxy fluorides KW - Chemical shift trend analysis KW - High field solid state NMR KW - Quadrupolar nuclei PY - 2008 DO - https://doi.org/10.1021/jp804662f SN - 1932-7447 SN - 1089-5639 VL - 112 IS - 40 SP - 15708 EP - 15720 PB - Soc. CY - Washington, DC AN - OPUS4-18365 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schmidt, T. A1 - Dai, Z. A1 - Drexler, H.-J. A1 - Baumann, W. A1 - Jäger, Christian A1 - Pfeifer, Dietmar A1 - Heller, D. T1 - Novel contributions to the mechanism of the enantioselective hydrogenation of dimethyl itaconate with rhodium complexes KW - Enantioselective Hydrogenation KW - Rhodium-Phosphor-Complex KW - Powder Diffractometry KW - Hr- and Solid State NMR-Spectroscpy KW - Asymmetric catalysis KW - Hydrogenation KW - Kinetics KW - Reaction mechanisms KW - Rhodium PY - 2008 DO - https://doi.org/10.1002/chem.200800389 SN - 0947-6539 SN - 1521-3765 VL - 14 IS - 15 SP - 4469 EP - 4471 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-18368 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maltsev, Sergey A1 - Jäger, Christian T1 - Solid-state NMR spectroscopy using the lost I spin magnetization in polarization transfer experiments N2 - A variation of the cross polarization (CP) experiment is discussed. The method requires two scans where the difference signal is equivalent to the I spin magnetization that is transferred to the S spins. The acquired signal is equivalent to F1 sum projection of a two-dimensional (2D) heteronuclear correlation experiment and is obtained by just two scans without the need to increment the indirect time domain t1. Any polarization transfer method and any kind of spin manipulations during the t1 incrementation period of a 2D NMR experiment can be applied. The method allows fast measurements of the CP transfer, particularly if various S spins signal overlap and is good for spectral editing of I spin signals with contact to S spins. Various examples for biomaterials are presented. Most importantly, this novel approach is ideal for detailed investigations of organic–mineral interfaces in bone, here demonstrated for O-phospho-L-serine as simple model compound. KW - NMR KW - Double resonance KW - Cross polarization KW - Heteronuclear correlation KW - Biomaterials KW - Hydroxyapaptite KW - Bone PY - 2008 DO - https://doi.org/10.1016/j.ssnmr.2008.08.001 SN - 0926-2040 SN - 1527-3326 VL - 34 IS - 3 SP - 175 EP - 179 PB - Academ. Press CY - Orlando, Fla. AN - OPUS4-18377 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pawlik, Alf A1 - Jäger, Christian T1 - Catalytically active High-Surface Aluminiumfluoride and its Precursor a Solid-State NMR Study. T2 - 6th Alpine Conference on Solid-State NMR CY - Chamonix, France DA - 2009-09-13 PY - 2009 AN - OPUS4-19374 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krahl, Thoralf A1 - Jäger, Christian T1 - Predicting Phase Compositions of CA10(K,Na)(PO4)7 Melts by 31PMAS NMR T2 - 22nd International Symposium of Ceramics in Medicine - Bioceramics 22 CY - Daegu, South Korea DA - 2009-10-26 PY - 2009 AN - OPUS4-19416 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Barheine, Sabrina A1 - Jäger, Christian T1 - Surface, interface and bulk structure of borate containing apatitic biomaterials T2 - The Alpine Conference on Solid-State NMR CY - Chamonix, France DA - 2009-09-13 PY - 2009 AN - OPUS4-19370 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Karrasch, Andrea A1 - Jäger, Christian T1 - Solid-state NMR Studies of Methyl Celluloses T2 - The Alpine Conference on Solid-State NMR CY - Chamonix, France DA - 2009-09-13 PY - 2009 AN - OPUS4-19372 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - NMR studies of short and medium range order in glasses and disordered surfaces of biomaterials T2 - MPG Summer School on Amorphous Solids in Physics and Biology CY - Neuhardenberg, Germany DA - 2009-06-01 PY - 2009 AN - OPUS4-19481 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Order and disorder in biominerals: News about bone and sea urchin spines. T2 - GDCh-Fachgruppenjahrestagung "Magnetische Resonanzspektroskopie" CY - Dresden, Germany DA - 2009-09-21 PY - 2009 AN - OPUS4-19526 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - König, R. A1 - Scholz, G. A1 - Pawlik, Alf A1 - Jäger, Christian A1 - Rossum, B. van A1 - Kemnitz, E. T1 - Identification of AIFx(OR)y species in strongly disordered aluminium isopropoxide fluoride solids: a field-dependent MAS NMR study KW - Ultra high-field MAS NMR (21.1T) KW - 27 Al MAS solid state NMR KW - Fluoride xerogels KW - Sol-gel process KW - Fluorolysis KW - Quadrupolar nuclei PY - 2009 DO - https://doi.org/10.1021/jp9066795 SN - 1932-7447 SN - 1089-5639 VL - 113 IS - 35 SP - 15576 EP - 15585 PB - Soc. CY - Washington, DC AN - OPUS4-20461 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bartoszek, M. A1 - Eckelt, R. A1 - Jäger, Christian A1 - Kosslick, H. A1 - Pawlik, Alf A1 - Schulz, A. T1 - Mesoporous silica-aluminas derived from precipitation: a study of the acidity, textural properties and catalytic performance KW - Silica-alumina KW - Solid state NMR KW - Acidity KW - Silicates KW - Tetrahedral aluminium PY - 2009 DO - https://doi.org/10.1007/s10853-009-3580-y SN - 0022-2461 SN - 1573-4803 VL - 44 IS - 24 SP - 6629 EP - 6636 PB - Springer Science + Business Media B.V. CY - Norwell, Mass. AN - OPUS4-20462 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pawlik, Alf A1 - König, R. A1 - Scholz, G. A1 - Kemnitz, E. A1 - Brunklaus, G. A1 - Bertmer, M. A1 - Jäger, Christian T1 - Access to local structures of HS-AIF3 and its precursor determined by high-resolution solid-state NMR KW - Aluminium fluoride KW - 27Al NMR KW - MQMAS KW - Amorphous materials KW - Catalysts PY - 2009 DO - https://doi.org/10.1021/jp904626k SN - 1932-7447 SN - 1089-5639 VL - 113 IS - 38 SP - 16674 EP - 16680 PB - Soc. CY - Washington, DC AN - OPUS4-20463 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krahl, Thoralf A1 - Gildenhaar, Renate A1 - Kenning, Hilke A1 - Berger, Georg A1 - Jäger, Christian ED - Kim, Sukyoung T1 - Predicting phase compositions of samples in the ternary system Ca2KNa(PO4)2-Ca3(PO4)2-Ca2P2O7 using 31P MAS NMR T2 - 22nd International symposium on ceramics in medicine (Bioceramics 22) CY - Daegu, Korea DA - 2009-10-26 KW - NMR KW - Bone substitute materials KW - Alkali calcium phosphates KW - TCP KW - Ca10(K,NA)(PO4)7 PY - 2009 SP - 11 EP - 14 AN - OPUS4-20656 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pawlowski, Kristin A1 - Schartel, Bernhard A1 - Fichera, Mario Augusto A1 - Jäger, Christian T1 - Flame retardancy mechanisms of bisphenol A bis(diphenyl phosphate) in combination with zinc borate in bisphenol A polycarbonate/Acrylonitrile-butadiene-styrene blends N2 - Bisphenol A polycarbonate/acrylonitrile–butadiene–styrene (PC/ABS) with and without bisphenol A bis(diphenyl phosphate) (BDP) and 5 wt.% zinc borate (Znb) were investigated. The pyrolysis was studied by thermogravimetry (TG), TG-FTIR and NMR, the fire behaviour with a cone calorimeter applying different heat fluxes, LOI and UL 94. Fire residues were examined with NMR. BDP affects the decomposition of PC/ABS and acts as a flame retardant in the gas and condensed phases. The addition of Znb results in an additional hydrolysis of PC. The fire behaviour is similar to PC/ABS, aside from a slightly increased LOI and a reduced peak heat release rate, both caused by borates improving the barrier properties of the char. In PC/ABS + BDP + Znb, the addition of Znb yields a borate network and amorphous phosphates. Znb also reacts with BDP to form alpha-zinc phosphate and borophosphates that suppress the original flame retardancy mechanisms of BDP. The inorganic–organic residue formed provides more effective flame retardancy, in particular at low irradiation in the cone calorimeter, and a clear synergy in LOI, whereas for more developed fires BDP + Znb become less effective than BDP in PC/ABS with respect to the total heat evolved. KW - Flame retardancy KW - PC/ABS KW - Aryl phosphate KW - Zinc borate KW - Flammability PY - 2010 DO - https://doi.org/10.1016/j.tca.2009.10.007 SN - 0040-6031 SN - 1872-762X VL - 498 IS - 1-2 SP - 92 EP - 99 PB - Elsevier CY - Amsterdam AN - OPUS4-20746 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Pikacz, E. A1 - Seefeldt, Henrik A1 - Schartel, Bernhard A1 - Braun, Ulrike A1 - Karrasch, Andrea A1 - Jäger, Christian T1 - Flame retardancy in PC/Silicone rubber blends using BDP and additional additives T2 - 20th Annual conference on recent advances in flame retardancy of polymeric materials CY - Stamford, CT, USA DA - 2009-06-01 KW - Flame retardancy KW - PC blend KW - Aryl phosphate PY - 2009 SN - 1-59623-509-8 VL - 20 IS - Chapter IV-B SP - 236 EP - 246 CY - Wellesley, MA, USA AN - OPUS4-20703 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reinsch, Stefan A1 - Dreßler, Martin A1 - Nofz, Marianne A1 - Pauli, Jutta A1 - Jäger, Christian A1 - Scholz, G. ED - Krämer, V. T1 - Phasentransformationen von anorganisch modifizierten Alumo-Xerogelen T2 - Jahrestagung der Gesellschaft für Thermische Analyse e.V. CY - Augsburg, Deutschland DA - 2003-09-15 PY - 2003 SP - 1 EP - 2 AN - OPUS4-2668 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - About nanocrystalline Hydroxyapatite and the binding of apatite in bone: a novel NMR perspective T2 - Vortrag am Max-Planck-Institut für Kolloid- und Grenzflächenforschung, Abteilung Biomaterialien CY - Potsdam, Germany DA - 2004-07-14 PY - 2004 AN - OPUS4-4636 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - About Nanocrystalline Hydroxyapatite and the Binding of Apatite in Bone: A Solid State-NMR Perspective T2 - 7th International Essen Symposium on Biomaterials and Biomechanics: Fundamentals and Clinical Applications CY - Essen, Germany DA - 2004-10-06 PY - 2004 AN - OPUS4-5501 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Nanocrystalline Hydroxyapatite and Apatite Binding in Bone: A Solid State-NMR Perspective T2 - EENC/Congress Ampere CY - Lille, France DA - 2004-08-06 PY - 2004 AN - OPUS4-5502 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - NMR studies of the structure of precipitated calcium phosphates and carbonates and of mineral protein interactions T2 - DFG-Antragskolloquium des Schwerpunktprogramms "Biomineralisation" CY - Bonn, Germany DA - 2005-02-21 PY - 2005 AN - OPUS4-7269 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - NMR studies of the structure of precipitated calcium phosphates and carbonates and of mineral protein interactions T2 - DFG-Antragskolloquium des Schwerpunktprogramms "Biomineralisation" CY - Bonn, Germany DA - 2005-02-21 PY - 2005 AN - OPUS4-7270 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Übersichtsposter über Expertise und Angebot der AG "NMR-Spektroskopie" zur Leitinitiative "NanoforLife" T2 - Auftaktveranstaltung zur Leitinnovation "NanoforLife" CY - Düsseldorf, Germany DA - 2005-01-26 PY - 2005 AN - OPUS4-7271 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - NMR characterization of nanocrystalline hydroxyapatite and of the mineral-protein interface in bone T2 - 46th ENC CY - Providence, RI, USA DA - 2005-04-11 PY - 2005 AN - OPUS4-7373 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - NMR characterization of nanocrystalline hydroxyapatite and of the mineral-protein interface in bone T2 - Workshop "Biomineralization"; University of Cambridge CY - Cambridge, England DA - 2005-04-18 PY - 2005 AN - OPUS4-7374 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Investigation of the Structure of Phosphate-Based Glasses using 170 NMR T2 - DFG-Berichtskolloquium 750MHz-Widebore-Spektrometer Leipzig CY - Leipzig, Germany DA - 2005-05-25 PY - 2005 AN - OPUS4-7549 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian A1 - Duer, M. J. T1 - Solid-state NMR: a tool for probing the protein-mineral interface and other structures in bone T2 - EUROMAR 2005/EENC 2005 CY - Veldhoven, Netherlands DA - 2005-07-03 PY - 2005 AN - OPUS4-7551 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - -NMR characterization of nanocrystalline hydroxyapatite and of the mineral-protein in bone T2 - Worshop "Biomineralization", Univ. Cambridge CY - Cambridge, England DA - 2005-04-18 PY - 2005 AN - OPUS4-7552 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - NMR characterization of nanocrystalline hydroxyapatite and of the mineral-protein interface in bone T2 - 46th ENC CY - Providence, RI, USA DA - 2005-04-11 PY - 2005 AN - OPUS4-7553 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - NMR characterization of nanocrystalline hydroxyapatite and of the mineral-protein interface in bone T2 - Tag der Chemie CY - Berlin, Germany DA - 2005-06-08 PY - 2005 AN - OPUS4-7555 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Complete Ring Assignment of Crystalline and Amorphous Cellulose Ia T2 - Symposium "New Developments in High Field NMR" CY - Leipzig, Germany DA - 2002-04-25 PY - 2002 AN - OPUS4-10871 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - NMR-Unrtersuchungen zur Struktur nanoskaliger Biomaterialien: Phosphate und Carbonate T2 - DFG-Rundtischgespräch "Magnetische Spektroskopie der Struktur und Dynamik nano- und mesoskopischer Systeme" CY - Hirschegg, Austria DA - 2005-09-04 PY - 2005 AN - OPUS4-10881 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - A solid state NMR study of the biomineral nacre T2 - GDCh-Fachgruppen-Jahrestagung "Magnetische Resonanzspektroskopie" CY - Mainz, Germany DA - 2005-09-26 PY - 2005 AN - OPUS4-10882 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Progress of structural elucidation of amorphous calcium phosphate (ACP) and hydroxyapatite (HAp): Disorder and surfaces as seen by solid state NMR T2 - Bioceramics 18 CY - Kyoto, Japan DA - 2005-12-05 PY - 2005 AN - OPUS4-10883 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - 17O NMR of Phosphate Glasses and Ambiguities of Comparative XRD and NMR Studies of Phosphate Biomaterials T2 - American Ceramic Society, Glass & Optical Materials Division Fall Meeting CY - Corning, NY, USA DA - 2003-10-01 PY - 2003 AN - OPUS4-3755 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Solid State NMR of Solid Bacterial Cellulose: Assignment of the Carbon Signals to the Ring Strukture T2 - Chemistry Departament, University of Cambridge CY - Cambridge, England DA - 2003-11-01 PY - 2003 AN - OPUS4-3756 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Solid State NMR and Materials Research: Examples from Glasses to Cellulose T2 - Berlin Magnetic Resonance Seminar CY - Berlin, Germany DA - 2003-03-13 PY - 2003 AN - OPUS4-3749 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - About Nanocrystalline Hydroxyapatite and Apatite Binding in Bone: A Solid State-NMR Perspective T2 - BRSG-Conference "Recent Advances and Applications of Solid State NMR", University of Warwick CY - Warwick, England DA - 2004-08-14 PY - 2004 AN - OPUS4-4767 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Observation of the Glycosidic Bond and Complete Ring Assignment of the 13C Signals of Bacterial Cellulose T2 - 45th Rocky Mountain Conference on Analytical Chemistry CY - Denver, CO, USA DA - 2003-07-27 PY - 2003 AN - OPUS4-4796 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - 17O NMR of Phosphate and Borophosphate Glasses T2 - 45th Rocky Mountain Conference on Analytical Chemistry CY - Denver, CO, USA DA - 2003-07-27 PY - 2003 AN - OPUS4-4797 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Observation of the Glycosidic Bond and Complete Ring Assignment of the 13C Signals of Bacterial Celllulose T2 - 3rd Alpine Conference on Solid-State NMR CY - Chamonix, France DA - 2003-09-14 PY - 2003 AN - OPUS4-4798 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Observation of the Glycosidic Bond and Complete Ring Assignment of the 13C Signals of Bacterial Cellulose T2 - 25. Jahrestagung der Fachgruppe "Magnetische Resonanzspektroskopie" CY - Leipzig, Germany DA - 2003-09-29 PY - 2003 AN - OPUS4-4882 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian A1 - Hartmann, P. A1 - Barth, S. A1 - Vogel, J. A1 - Pauli, Jutta A1 - Schmauder, H.-P. T1 - NMR und Biomaterialien - Was kann man über plasmagespritzte Apatitschichten und Cellulose lernen? T2 - Kolloquium des SFB 428 CY - Freiburg, Deutschland DA - 2002-12-10 PY - 2002 AN - OPUS4-2127 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spange, S. A1 - Seifert, Alexander A1 - Müller, Hansjörg A1 - Hesse, S. A1 - Jäger, Christian T1 - Fabrication of chromophoric xerogels by senergistic combination of nucleophilic aromatic substitution and the sol-gel process N2 - The nucleophilic substitution of fluorine of aromatic compounds with n-aminoalkyl trialkoxysilanes and consecutive sol-gel process have been used for the fabrication of various chromophoric sol-gel materials. The displacement of the fluoro substituent of an activated aromatic molecule occurs by a primary or secondary amino group of (CH3O)3Si-(CH2)3-NHR [R- = H-; CH3-, (CH3O)3Si-(CH2)3-] in tetraalkoxysilane or alcohol as solvent and the sol-gel process can be carried in the same vessel. The HF formed is trapped by a tertiary amine and simultaneously serves as the catalyst for the sol-gel process. Various aromatic compounds have been checked for this purpose: 1-(4-fluorophenyl)-2-nitroethylene, 1-(4-fluorophenyl)-2,2-dicyanoethylene, 4-fluorobenzonitrile, 4-fluoronitrobenzene, 4,4prime-difluorobenzophenone, 4,4prime-difluorobenzil, 7,7prime-difluorodibenzylideneacetone, tetrafluoro-p-benzoquinone, and 1,5-difluoro-2,4-dinitrobenzene. Mono and disubstitution has been studied by UV/Vis- and solid state NMR spectroscopy of the xerogels. PY - 2003 DO - https://doi.org/10.1023/A:1020789318803 SN - 0928-0707 SN - 1573-4846 VL - 26 SP - 77 EP - 81 PB - Kluwer Academic Publ. CY - Dordrecht AN - OPUS4-2128 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Peuker, Christel A1 - Reinholz, Uwe A1 - Jäger, Christian A1 - Pauli, Jutta A1 - Geißler, Heinz T1 - Extinction coefficients of the OH bands in the IR spectra of basic and water-enriched silicate and aluminosilicate glasses PY - 2003 SN - 0927-4472 VL - 76 IS - 5 SP - 227 EP - 233 PB - Elsevier CY - Amsterdam AN - OPUS4-2781 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Materialanalytik: Was leistet die Festkörper NMR T2 - Kolloquium, BAM CY - Berlin, Germany DA - 2002-01-30 PY - 2002 AN - OPUS4-2949 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Was kann die NMR bei der Untersuchung von Kristallisationsvorgängen leisten: Eine kritische Wertung Deutsche Gesellschaft für Kristallographie, AK Nichtkristalline Strukturen T2 - XXIII Arbeitskreistagung CY - Jena, Germany DA - 2002-09-09 PY - 2002 AN - OPUS4-2950 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Ringzuordnung der Kohlenstoffsignale von Cellulose mittels 2D-NMR T2 - DFG-Rundtischgespräch "Magnetische Resonanz zur Abstandsbestimmung und neue Methoden zur Steigerung von Sensitivität und Auflösung" CY - Hirschegg, Austria DA - 2002-09-18 PY - 2002 AN - OPUS4-2951 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - 170 NMR of Binary and Ternary Phosphate Glasses T2 - 7th Otto Schott Collquium CY - Jena, Germany DA - 2002-07-04 PY - 2002 AN - OPUS4-2954 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Was lernt man aus NMR-Untersuchungen fester Bakteriencellulose? T2 - Biotechnologie-Kolloquium anlässlich des 10-jährigen Bestehens des Forschungszentrums für Medizintechnik und Biotechnologie e. V. CY - Bad Langensalza, Germany DA - 2004-06-30 PY - 2004 AN - OPUS4-4076 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Das Bio- und Knochenmaterial Apatit: Zur Struktur von nanokristallinem Apatit und über die Bindung von Apatit im Knochen T2 - 10. MDR-Treffen, Universität Leipzig CY - Leipzig, Germany DA - 2004-07-12 PY - 2004 AN - OPUS4-4127 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Adorjan, I. A1 - Rosenau, Th. A1 - Potthast, A. A1 - Kosma, P. A1 - Mereiter, K. A1 - Pauli, Jutta A1 - Jäger, Christian T1 - Crystal and molecular structure of methyl 4-O-methyl-beta-D-ribo-hex-3-ulopyranoside N2 - Methyl 4-O-methyl-?-Image-ribo-hex-3-ulopyranoside (2), a model compound for partially oxidized anhydroglucose units in cellulose, was crystallized from CHCl3/n-hexane by vapor diffusion to give colorless plates. Crystal structure determination revealed the monoclinic space group P21 with Z=2C8H14O6 and unit cell parameters of a=8.404(2), b=4.5716(10), c=13.916(3) Å, and ?=107.467(4)°. The structure was solved by direct methods and refined to R=0.0476 for 1655 reflections and 135 parameters. The hexulopyranoside occurs in a distorted chair conformation. Both hydroxyls are involved in hydrogen bonding and form zigzag bond chains along the b-axis. One of the two hydrogen bonds is bifurcated. The solid-state 13C NMR spectrum of 2 exhibits eight carbon resonances, with well-separated signals for the two methoxyls (1-OMe: 55.72 ppm, 4-OMe: 61.25 ppm) and a keto resonance with relatively large downfield shift (206.90 ppm). Differences in the C-4 and the methoxyls’ chemical shifts in the solid and liquid states were found KW - Crystal structure KW - Solid-state NMR KW - Cellulose KW - Carbonyl groups PY - 2004 DO - https://doi.org/10.1016/j.carres.2004.01.006 SN - 0008-6215 SN - 1873-426X VL - 339 IS - 4 SP - 795 EP - 799 PB - Elsevier CY - Amsterdam AN - OPUS4-5341 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - 17O NMR of Phosphate Glasses and Ambiguities of Comparative XRD and NMR Studies of Phosphate Bioceramics T2 - American Ceramic Society, Glass & Optical Materials Division Fall Meeting CY - Corning, NY, USA DA - 2003-10-12 PY - 2003 AN - OPUS4-5312 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Neues aus der Nanowelt: Über Strukturen, Oberflächen und die Mineral-Protein-Wechselwirkung in Biomaterialien T2 - 13. Keramiktag der BAM CY - Berlin, Germany DA - 2006-05-09 PY - 2006 AN - OPUS4-12388 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jäger, Christian A1 - Welzel, T. A1 - Meyer-Zaika, W. A1 - Epple, M. T1 - A solid-state NMR investigation of the structure of nanocrystalline hydroxyapatite N2 - Nanocrystalline hydroxyapatite (HAp) prepared by a precipitation route was investigated. The X-ray diffraction (XRD) powder patterns of the elongated nanocrystals with a typical diameter of about 10 nm and length of 30-50 nm (by transmission electron microscopy (TEM)) revealed the presence of HAp with significantly broadened XRD reflections. However, Ca deficiency was found, as the Ca/P ratio was 1.5 only (so-called calcium-deficient hydroxyapatite (CDHA)), and not 1.67. This Ca deficiency of nanocrystalline HAp is explained using NMR. It is shown unambiguously that (i) the nanocrystals consist of a crystalline core and a (disordered) surface region with a relative phosphate content of about 1:1, (ii) the crystalline core is HAp, and (iii) the surface region is dominated by hydrogen phosphate anions (with no hydroxyapatite-like structural motif) and structural water (hydrate). From the relative phosphate content and taking into account the crystal shape, the thickness of the surface layer along the main crystal axis could be estimated to be about 1 nm, and the average chemical composition of the surface layer has been determined. Finally, a Ca/P ratio of 1.52 was estimated from the NMR data that compares well with the value of 1.51 from chemical analysis. The important consequences are that the surface of nanocrystalline HAp has nothing in common with the bulk composition and that the chemistry of such materials (e.g. the binding of protein molecules to phosphate surfaces) must be reconsidered. KW - NMR KW - H-1 KW - P-31 KW - Biomineralization KW - Hydroxyapatite KW - Calcium phosphate KW - Nanoparticles PY - 2006 DO - https://doi.org/10.1002/mrc.1774 SN - 0749-1581 SN - 1097-458X VL - 44 IS - 6 SP - 573 EP - 580 PB - Wiley CY - Chichester AN - OPUS4-12366 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nofz, Marianne A1 - Pauli, Jutta A1 - Dreßler, Martin A1 - Jäger, Christian A1 - Altenburg, Wolfgang T1 - 27Al NMR Study of Al-Speciation in Aqueous Alumina-Sols N2 - A new method of preparing concentrated alumo-sols, the hydrolysis of Al-tri-sec-butylate in acidic aqueous media at 85°C, was studied in detail by varying the H2O/Al- and NO3 -/Al-ratios in wide ranges. The components of the sols were characterized by 27Al NMR spectroscopy. The pH-value depends on both the chosen H2O/Al- and NO3 -/Al-ratio and on the aging time of the sols and reflects the composition of the sols. Al13 polycations were detected in sols with a pH-value between 3.0 and 3.7. As a new result its presence was shown by NMR below 3.4. The Al13 content of the sols increased with pH and the maximum fraction of Al13 polycations was detected in the sol with the highest pH (3.7). Nearly 65% of the entire aluminium content of this solution is bound in the Al13 polycations. Hence, a new synthetic method for the preparation of Al13 ions containing sols was developed. Aging studies of the sols showed, that the Al13 polycations were more stable in solutions with higher pH-value. Al13 polycations were detected after an aging time of four months only in sols with a pH-value of 3.7. Tempering the aged sols at 40° to 80°C caused formation of Al13 and also of Al30 polycations. KW - Alumo-sol KW - Al13 polycations KW - Al-27 NMR spectroscopy PY - 2006 SN - 0928-0707 SN - 1573-4846 VL - 38 IS - 1 SP - 25 EP - 35 PB - Kluwer Academic Publ. CY - Dordrecht AN - OPUS4-12350 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - A solid state NMR study of the biomaterial nacre T2 - Rocky Mountain Conference on Analytical Chemistry CY - Breckenridge, CO, USA DA - 2006-07-24 PY - 2006 AN - OPUS4-12387 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - NMR of synthetic and natural biomaterials T2 - Seminar an der Universität Yokohama CY - Yokohama, Japan DA - 2006-06-19 PY - 2006 AN - OPUS4-12492 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jäger, Christian A1 - Maltsev, Sergey A1 - Karrasch, Andrea T1 - Progress of Structural Elucidation of Amorphous Calcium Phosphate (ACP) and Hydroxyapatite (HAp): Disorder and Surfaces as Seen by Solid State NMR KW - Hydroxyapatite KW - Amorphous calcium phosphate KW - Structural investigation KW - Surface KW - NMR PY - 2006 VL - 18 IS - 1 SP - 69 EP - 72 AN - OPUS4-11008 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nassif, N. A1 - Pinna, N. A1 - Gehrke, N. A1 - Antonietti, M. A1 - Jäger, Christian A1 - Cölfen, H. T1 - Amorphous layer around aragonite platelets in nacre KW - Nacre KW - NMR KW - Aragonite KW - Amorphous Surface KW - Protein binding PY - 2005 SN - 0027-8424 SN - 1091-6490 VL - 102 IS - 36 SP - 12653 EP - 12655 PB - National Academy of Sciences CY - Washington, DC AN - OPUS4-11009 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jäger, Christian A1 - Groom, N. S. A1 - Bowe, Elizabeth A. A1 - Horner, A. A1 - Davies, M. Elisabeth A1 - Murray, Rachel C. A1 - Duer, M. J. T1 - Investigation of the Nature of the Protein-Mineral Interface in Bone by Solid-State NMR N2 - Hydrogen-bearing species in the bone mineral environment were investigated using solid-state NMR spectroscopy of powdered bone, deproteinated bone, and B-type carbonated apatite. Using magic-angle spinning and cross-polarization techniques three types of structurally-bound water were observed in these materials. Two of these water types occupy vacancies within the apatitic mineral crystal in synthetic carbonated apatite and deproteinated bone and serve to stabilize these defect-containing crystals. The third water was observed at the mineral surface in unmodified bone but not in deproteinated bone, suggesting a role for this water in mediating mineral-organic matrix interactions. Direct evidence of monohydrogen phosphate in a 1H NMR spectrum of unmodified bone is presented for the first time. We obtained clear evidence for the presence of hydroxide ion in deproteinated bone by 1H MAS NMR. A 1H-31P heteronuclear correlation experiment provided unambiguous evidence for hydroxide ion in unmodified bone as well. Hydroxide ion in both unmodified and deproteinated bone mineral was found to participate in hydrogen bonding with neighboring water molecules and ions. In unmodified bone mineral hydroxide ion was found, through a 1H-31P heteronuclear correlation experiment, to be confined to a small portion of the mineral crystal, probably the internal portion. KW - NMR KW - Bone KW - Protein-mineral-interface PY - 2005 DO - https://doi.org/10.1529/biophysj.105.070243 SN - 0897-4756 SN - 1520-5002 VL - 17 IS - 12 SP - 3059 EP - 3061 PB - American Chemical Society CY - Washington, DC AN - OPUS4-11010 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hesse, S. A1 - Jäger, Christian T1 - Determination of the 13C chemical shift anisotropies of cellulose I and cellulose II N2 - The chemical shift anisotropies (CSAs) of cellulose I and I, the two crystalline constituents of bacterial cellulose produced by Acetobacter xylinum (DSM 14666), and regenerated cellulose II are reported for each of the spectroscopically resolved carbon resonances using the phase adjusted spinning sideband (PASS) experiment. The data are compared with experimental results using the recoupling of anisotropy information (RAI) technique and with theoretical calculations of the structure of cellulose, including the hydrogen bonding systems. KW - Acetobacter xylinum KW - Bacterial cellulose KW - Cellulose I KW - Cellulose II KW - Chemical shift anisotropy KW - CSA KW - C-13 NMR PY - 2005 DO - https://doi.org/10.1023/B:CELL.0000049407.56737.c7 SN - 0969-0239 SN - 1572-882X VL - 12 IS - 1 SP - 5 EP - 14 PB - Chapman & Hall CY - London AN - OPUS4-11011 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koudelka, L. A1 - Mosner, P. A1 - Zeyer, M. A1 - Jäger, Christian T1 - Structural study of PbO-B2O3-P2O5 glasses by NMR, Raman and infrared spectroscopy T2 - 19th International Congress on Glass CY - Edinburgh, Scotland, UK DA - 2001-07-01 PY - 2002 SN - 0-900682-39-6 N1 - Serientitel: Physics and chemistry of glasses – Series title: Physics and chemistry of glasses VL - 43C IS - 43C.2002 SP - 1 EP - 6 PB - Soc. of Glass Techn. CY - Sheffield AN - OPUS4-11012 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zeyer, M. A1 - Montagne, L. A1 - Kostoj, V. A1 - Palavit, G. A1 - Prochnow, D. A1 - Jäger, Christian T1 - 17O nuclear magnetic resonance study of Na2O-P2O5 glasses N2 - The preparation and structural investigation of 17O-enriched xNa2O–(100-x)P2O5 glasses (46.5<=x<=62.8) by nuclear magnetic resonance (NMR) is described. Enriched phosphoric acid was prepared by hydrolysis of PCl5 with 17O-enriched water and neutralized with sodium carbonate. The sodium metaphosphate was then melted at 800 °C for 15 h and quenched. Polyphosphate and ultraphosphate glass compositions were prepared by remelting the metaphosphate with sodium carbonate and phosphorus pentoxide, respectively. 31P magic angle sample spinning (MAS) NMR was used to determine the Na2O/P2O5 content in the glasses. 17O NMR spectra (quadrupole echo for non-rotating samples and multiple-quantum excitation for rotating samples (MQMAS)) show two oxygen sites in the samples with large quadrupolar coupling constants (4.7 and 7.7 MHz), in accordance with the high phosphorus electronegativity. According to the correlation of 17O quadrupolar constants with bond ionicity, these two components are attributed to bridging P–O–P and non-bridging P–O...Na oxygens. The average P–O–P bond angle is estimated with the quadrupolar asymmetry derived from the fit of the static echo spectra. The MQMAS spectrum shows a distribution of non-bridging oxygen chemical shifts, attributed to a variation of bond length and angle. PY - 2002 SN - 0022-3093 VL - 311 IS - 3 SP - 223 EP - 232 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-11013 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rosenau, Th. A1 - Mereiter, K. A1 - Jäger, Christian A1 - Schmid, P. A1 - Kosma, P. T1 - Sulfonium ylides derived from 2-hydroxy-benzoquinones: crystal and molecular structure and their one-step conversion jinto Mannich bases by amine N-oxides N2 - Reaction of 2-hydroxy-para-benzoquinones with DMSO/Ac2O produced dimethylsulfonium ylides, of which crystal structures as well as solid and liquid state NMR spectra were recorded. The ylides react with tertiary methylamine N-oxides in a one-pot, multi-step process to 3-methylamino-substituted benzoquinones. The mechanism starts with a deoxygenative deprotonation of the amine N-oxides, followed by a formal electrophilic displacement of DMSO by the resulting carbonium–iminium ion. KW - Sulfonium ylides KW - Amine N-oxides KW - Crystal structure KW - Benzoquinones PY - 2004 DO - https://doi.org/10.1016/j.tet.2004.05.015 SN - 0040-4020 SN - 1464-5416 VL - 60 IS - 27 SP - 5719 EP - 5723 PB - Elsevier Science CY - Kidlington AN - OPUS4-11014 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zeyer-Düsterer, Michaela A1 - Montagne, L. A1 - Palavit, G. A1 - Jäger, Christian T1 - Combined 17O NMR and 11B-31P double resonance NMR studies of sodium borophosphate glasses N2 - 17O enriched sodium borophosphate glasses were prepared from isotopically enriched NaPO3 and H3BO3. These glasses have been studied by 17O, 11B and 31P NMR including 17O and 11B multiple quantum magic angle sample spinning (MQMAS), 11B–31P heteronuclear correlation (HETCOR) NMR and 11B 31P rotational echo double resonance (REDOR). For comparison, the crystalline borophosphates BPO4 and Na5B2P3O13 were included in the investigations. The latter compound shows three sharp 31P resonances at -0.2, -2 and -8 ppm and two BO4 sites that can only be resolved by MQMAS. The 17O NMR spectra were recorded using both the static echo method at medium magnetic field (9.4 T) as well as MAS and MQMAS methods at high field (17.6 T). In total, five oxygen sites were identified in these borophosphate glasses: P–O–P, NaO–P, P–O–B, B–O–B, NaO–B. However, these five sites are not present simultaneously in any of the glasses. The 17O MQMAS spectra prove that P–O–B links play a major role in borophosphate glasses. These results are confirmed by the complementary 11B MAS spectra that show the presence of asymmetric and symmetric trigonal groups BO3a and BO3s and two tetrahedral BO4 units. 11B 31P REDOR NMR is used to give independent information to assign the 11B lines to structural units present in the glasses. These REDOR measurements reveal that B–O–P bonds are present for each borate unit, including the BO3 groups. Particularly, a structural proposal for the two different BO4 resonances is given in terms of a different number of bonded phosphate tetrahedra. The 31P MAS spectra are usually broad and not well resolved. It is shown by 11B–31P HETCOR NMR that a possible structural assignment of a 31P signal at about -20 ppm to Q2 units as in binary sodium phosphate glasses is wrong and that the phosphate tetrahedron belonging to this resonance must be connected to borate groups KW - NMR KW - Sodium borophosphate glasses KW - Glass structure KW - NA5B2P3O13 KW - O-17 NMR KW - REDOR KW - MQMAS PY - 2005 DO - https://doi.org/10.1016/j.ssnmr.2004.06.009 SN - 0926-2040 SN - 1527-3326 VL - 27 IS - 1-2 SP - 50 EP - 64 PB - Academ. Press CY - Orlando, Fla. AN - OPUS4-11015 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koudelka, L. A1 - Mosner, P. A1 - Zeyer, M. A1 - Jäger, Christian T1 - Structure and properties of mixed sodium-lead borophosphate glasses N2 - Mixed sodium–lead borophosphate glasses were prepared in two compositional series xNa2O–(50 - x)PbO–10B2O3–40P2O5 and xNa2O–(50 - x)PbO–20B2O3–30P2O5 with x = 0, 10, 20, 30, 40 and 50 mol% Na2O. Their density decreases and molar volume increases slightly with increasing Na2O content. Chemical durability decreases steeply for glasses containing 40–50 mol% Na2O, whereas glass transition temperatures reveals a minimum at the glasses with 30–40 mol% Na2O. The 31P MAS NMR and Raman spectra of the first series show that with increasing Na2O content the ratio of structural units Q2/Q1 slowly increases and the Q2 phosphate units and BO4 units prevail in the structure of these glasses. In the second series of glasses Q1 diphosphate units together with BO4 and small number of BO3 units form structural network of glasses. The replacement of PbO by Na2O results in higher ionicity of bonding interactions between compensating cations and the anionic network. The lower cation field strength of Na+ ions results in the observed downfield shift of ? (31P) values in Na-rich glasses and narrower vibrational bands in their Raman spectra. PY - 2005 DO - https://doi.org/10.1016/j.jnoncrysol.2005.01.015 SN - 0022-3093 VL - 351 IS - 12-13 SP - 1039 EP - 1045 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-11016 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - NMR-Untersuchungen zur Struktur nanoskaliger Biomaterialien: Über Strukturen an Oberflächen und die Mineral-Protein-Wechselwirkung am Knochen T2 - Seminarvortrag Makromolekulare Chemie, AK Blümich, RWTH CY - Aachen, Germany DA - 2005-06-14 PY - 2005 AN - OPUS4-11512 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - A solid state NMR study of the biomaterial nacre T2 - GDCh-Fachgruppe-Jahrestagung 2005 CY - Mainz, Germany DA - 2005-09-28 PY - 2005 AN - OPUS4-11519 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian A1 - Duer, M. J. T1 - Solid-state NMR: a tool for probing the protein-mineral interface in biomaterials T2 - Gordon Conference on Biomineralization CY - New London, NH, USA DA - 2006-07-30 PY - 2006 AN - OPUS4-11521 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - NMR-Untersuchungen zur Struktur nanoskaliger Biomaterialien: Phosphate und Carbonate T2 - DFG-Rundtischgespräch "Magnetische Spektroskopie der Struktur und Dynamik nano- und mesoskopischer Systeme" CY - Hirschegg, Austria DA - 2005-09-04 PY - 2005 AN - OPUS4-11522 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - NMR of nanoscopic inorganic biomaterials: on bulk structures, surfaces and the mineral-protein interface T2 - Graduiertenkolleg "Magnetische Resonanz", Universität Stuttgart CY - Stuttgart, Germany DA - 2005-11-07 PY - 2005 AN - OPUS4-11502 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Nanoskalige Calciumphosphate, Oberflächenstrukturen und Wechselwirkung mit organischen Molekülen. Was kann die NMR? T2 - Jahrestagung der Deutschen Gesellschaft für Biomaterialien e. V. CY - Würzburg, Germany DA - 2005-10-07 PY - 2005 AN - OPUS4-11505 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Spange, St. A1 - Müller, H. A1 - Jäger, Christian A1 - Bellmann, C. T1 - Fabrication of carbon/silica hybrid materials using cationic polymerization and the sol-gel process PY - 2002 SN - 1022-1360 SN - 0258-0322 SN - 1521-3900 VL - 177 IS - 1 SP - 111 EP - 124 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-11017 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zeyer, M. A1 - Montagne, L. A1 - Jäger, Christian T1 - Measuring oxygen-phosphorus distances and the orientation of electric field gradient tensors using 17O-{31P} REDOR in phosphate glasses N2 - Rotational echo double resonance (REDOR) of spin- nuclei is an extremely useful tool for the determination of distances in solids as well as of relative orientations of chemical shift and dipole tensors. We present the corresponding version for measuring the relative orientation of electric quadrupole and dipole tensors and demonstrate its applicability for non-bridging oxygens in phosphate glasses using 17O–{31P} REDOR NMR. The orientational information is found in the changes of the second-order quadrupole patterns as a function of the echo delay. Results and numeric simulations are presented for 17O–{31P} REDOR NMR of 17O-enriched sodium phosphate glasses. For non-bridging oxygens, the symmetric quadrupole tensor is found to be aligned along the phosphorus–oxygen bond. The distance between P and the non-bridging oxygen is calculated for two glasses of different compositions. KW - REDOR KW - Quadrupolar nuclei KW - O-17-{P-31} double resonance KW - Phosphate glasses PY - 2003 DO - https://doi.org/10.1016/S0926-2040(03)00012-2 SN - 0926-2040 SN - 1527-3326 VL - 23 IS - 3 SP - 136 EP - 144 PB - Academ. Press CY - Orlando, Fla. AN - OPUS4-11018 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meyer, T. A1 - Spange, St. A1 - Hesse, S. A1 - Jäger, Christian A1 - Bellmann, C. T1 - Radical Grafting Polymerization of Vinylformamide with Functionalized Silica Particles N2 - Two different radical polymerization techniques have been applied to covalently graft vinylformamide (VFA) onto silica particles. Grafting by the polymerization of VFA using an immobilized azo initiator on silica has been found less effective, because monomer conversion is limited in non-aqueous solvents and grafting yields are low in water. Radical copolymerization of VFA with vinyltriethoxysilane (VTS)-functionalized silica particles is suitable to produce poly(vinylformamide) (PVFA) silica hybrid particles in respectable yield. The VFA/VTS-silica ratio determines the degree of grafting. The PVFA-VTS-co-grafted silica particles can be acidically hydrolyzed into poly(vinylamine)-grafted silica particles. Molecular structures of the surface groups and grafted polymer chains have been confirmed by means of solid state 13C{1H} cross-polarization magic-angle spinning (CP MAS) NMR spectroscopy. Zeta potential measurements show the altering of the former silica particles surface charges arising from the introduction of basic groups on the surface. KW - Composites KW - Copolymerization KW - Graft copolymers KW - Polyamines KW - Surfaces PY - 2003 DO - https://doi.org/10.1002/macp.200390042 SN - 1022-1352 SN - 1521-3935 VL - 204 IS - 4 SP - 725 EP - 732 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-11019 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koudelka, L. A1 - Mosner, P. A1 - Zeyer, M. A1 - Jäger, Christian T1 - Lead borophosphate glasses doped with titanium dioxide N2 - Glasses of the compositional series of 50PbO–yB2O3–(50-y)P2O5–xTiO2 (with x=0–16) have been prepared and characterized by the determination of density, molar volume, glass transition temperature, dilatation softening temperature, thermal and chemical durability. Structural changes were evaluated from the studies by 31P and 11B MAS NMR, Raman and infrared spectroscopy. Molar volume of the glasses decreases and the glass transition temperature increases with increasing additions of TiO2. 31P MAS NMR spectra revealed that titanate units enter phosphate chains decreasing the number of Q2 units and increasing the number of Q1 units. This result is confirmed by the observed changes in the Raman and infrared spectra of the TiO2-doped glasses. PY - 2003 DO - https://doi.org/10.1016/S0022-3093(03)00380-6 SN - 0022-3093 VL - 326-327 SP - 72 EP - 76 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-11020 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koudelka, L. A1 - Mosner, P. A1 - Petrík, J. A1 - Zeyer, M. A1 - Jäger, Christian T1 - Study of the structure of mixed lead borophosphate glasses by NMR, RAMAN and IR Spectroscopy PY - 2002 SN - 0918-4783 VL - 13 SP - 165 EP - 170 CY - Tokyo AN - OPUS4-11021 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zeyer, M. A1 - Montagne, L. A1 - Jäger, Christian A1 - Palavit, G. T1 - 17O NMR of Crystalline Sodium Trimetaphosphate PY - 2002 SN - 0918-4783 VL - 13 SP - 275 EP - 278 CY - Tokyo AN - OPUS4-11022 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mackie, I.D. A1 - Röhrling, J. A1 - Gould, R.O. A1 - Pauli, Jutta A1 - Jäger, Christian A1 - Walkinshaw, M. A1 - Potthast, A. A1 - Rosenau, Th. A1 - Kosma, P. T1 - Crystal and molecular structure of methyl 4-O-methyl-beta-D-glucopyranosyl-(1->4)-beta-D-glucopyranoside N2 - The cellulose model compound methyl 4-O-methyl-?-Image-glucopyranosyl-(1?4)-?-Image-glucopyranoside (6) was synthesised in high overall yield from methyl ?-Image-cellobioside. The compound was crystallised from methanol to give colourless prisms, and the crystal structure was determined. The monoclinic space group is P21 with Z=2 and unit cell parameters a=6.6060 (13), b=14.074 (3), c=9.3180 (19) Å, ?=108.95(3)°. The structure was solved by direct methods and refined to R=0.0286 for 2528 reflections. Both glucopyranoses occur in the 4C1 chair conformation with endocyclic bond angles in the range of standard values. The relative orientation of both units described by the interglycosidic torsional angles [? (O-5?---C-1?---O-4---C-4) -89.1°, phi (C-1?---O-4---C-4---C-5) -152.0°] is responsible for the very flat shape of the molecule and is similar to those found in other cellodextrins. Different rotamers at the exocyclic hydroxymethyl group for both units are present. The hydroxymethyl group of the terminal glucose moiety displays a gauche–trans orientation, whereas the side chain of the reducing unit occurs in a gauche–gauche conformation. The solid state 13C NMR spectrum of compound 6 exhibits all 14 carbon resonances. By using different cross polarisation times, the resonances of the two methyl groups and C-6 carbons can easily be distinguished. Distinct differences of the C-1 and C-4 chemical shifts in the solid and liquid states are found. KW - Crystal structure KW - Cellulose KW - Methyl cellobioside KW - Solid state NMR PY - 2002 DO - https://doi.org/10.1016/S0008-6215(01)00299-3 SN - 0008-6215 SN - 1873-426X VL - 337 IS - 2 SP - 161 EP - 166 PB - Elsevier CY - Amsterdam AN - OPUS4-11023 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jäger, Christian A1 - Maltsev, Sergey A1 - Malz, Frank A1 - Karrasch, Andrea A1 - Altenburg, Wolfgang T1 - Nanoskalige Calciumphosphate, Oberflächenstrukturen und Wechselwirkung mit organischen Molekülen: Was kann die NMR? PY - 2005 SN - 1616-0177 SN - 0011-8656 VL - 6 IS - 3 SP - 232 PB - Verl. Neuer Merkur CY - München AN - OPUS4-11609 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - NMR characterisation of bulk and surface structures of nanoscopic phosphates and carbonates T2 - DFG-Berichtskolloquium SPP 1117 "Biomineralisation" CY - Bad Honnef, Germany DA - 2006-10-08 PY - 2006 AN - OPUS4-13809 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - NMR-Untersuchungen zum thermischen Abbau von flammgeschützten Polymeren T2 - Projekttreffen, BAM - Stammgelände CY - Berlin, Germany DA - 2006-08-22 PY - 2006 AN - OPUS4-13810 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Malz, Frank A1 - Yoneda, Y. A1 - Kawada, T. A1 - Mereiter, K. A1 - Kosma, P. A1 - Rosenau, T. A1 - Jäger, Christian T1 - Synthesis of methyl 4'-O-methyl-beta-D-cellobioside-13C12 from D-glucose-13C6. Part 2: Solid-state NMR studies KW - Cellodextrins KW - Cellulose KW - Model compounds KW - Solid-state NMR KW - Glycosidic bond KW - C-13 isotopic labeling PY - 2007 SN - 0008-6215 SN - 1873-426X VL - 342 IS - 1 SP - 65 EP - 70 PB - Elsevier CY - Amsterdam AN - OPUS4-14450 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian A1 - Fichera, Mario Augusto T1 - Solid-State NMR for monitoring the thermal Decomposition of flame retarded polymers T2 - 49th Annual Rocky Mountain Conference on Analytical Chemistry, Beaver run Resort & Conference Center CY - Breckenridge, CO, USA DA - 2007-07-22 PY - 2007 AN - OPUS4-14687 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - 13C{31P} REDOR solid state NMR proves the organic-mineral interface in bone is stabilized by polysaccarides T2 - 49th Rocky Mountain Conference on Analytical Chemistry, Beaver Run Resort & Conference Center CY - Breckenridge, CO, USA DA - 2007-07-22 PY - 2007 AN - OPUS4-14704 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koudelka, L. A1 - Mosner, P. A1 - Jirák, J. A1 - Zeyer-Düsterer, Michaela A1 - Jäger, Christian T1 - Medium range order in lead borophosphate glasses N2 - The structure of 50PbO-xB2O3-(50-x)P2O5 glasses with x=0-25 mol% B2O3 was refined by Raman and 11B MQMAS NMR. The analysis of Raman spectra, using the concentration step of 2 mol% B2O3 within the range of 0-12 mol% B2O3, showed that the evolution of changes in the type of oxygen bridges can be observed from the Raman bands within the range of 600-800 cm-1. 11B MQMAS NMR spectra of glasses with x=15, 20 and 25 mol% B2O3 revealed the presence of two BO4 sites in these glasses. The first site B1O4, characterised by the chemical shift of d=-3·8 — (-3·4) ppm, was assigned to tetrahedral B(OP)4 structural units. Within the concentration range x=15-25 mol% B2O3, the site B1O4 is gradually replaced by the site B2O4 with the chemical shift of d=-1·8 — (-1·1) ppm. This second site was assigned to the presence of B(OP)3(OB) units in which the central boron atom is linked to three PO4 groups and one BO3 group. KW - NMR KW - Raman KW - Struktur KW - Gläser PY - 2006 SN - 0031-9090 VL - 47 IS - 4 SP - 471 EP - 475 PB - Thornton CY - Sheffield AN - OPUS4-14811 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Braun, Ulrike A1 - Schartel, Bernhard A1 - Fichera, Mario Augusto A1 - Jäger, Christian T1 - Flame retardancy mechanisms of aluminium phosphinate in combination with melamine polyphosphate and zinc borate in glass-fibre reinforced polyamide 6,6 N2 - The fire retardancy mechanisms of aluminium diethylphosphinate in combination with melamine polyphosphate and zinc borate was analysed in glass-fibre reinforced polyamide 6,6. The influence of phosphorus compounds on the polyamide decomposition pathways was characterized using thermal analysis (TG), evolved gas analysis (TG–FTIR), and FTIR–ATR analysis of the residue. The Lewis acid–base interactions between the flame retardants, the amide unit, and the metal ions control the decomposition. The flammability (LOI, UL 94) and performance under forced-flaming conditions (cone calorimeter using different irradiations) were investigated. Fire residues were analysed with FTIR–ATR, SEM–EDX, and NMR. Aluminium phosphinate in polyamide 6,6 acts mainly by flame inhibition. Melamine polyphosphate shows some fuel dilution and a significant barrier effect. Using a combination of aluminium phosphinate and melamine polyphosphate results in some charring and a dominant barrier effect. These effects are improved in the presence of zinc borate due to the formation of boron–aluminium phosphates instead of aluminium phosphates. KW - Flame retardancy KW - Polyamide 6,6 KW - Metal phosphinate KW - Melamine polyphosphate KW - Zinc borate PY - 2007 SN - 0141-3910 SN - 1873-2321 VL - 92 IS - 8 SP - 1528 EP - 1545 PB - Applied Science Publ. CY - London AN - OPUS4-15707 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dreßler, Martin A1 - Nofz, Marianne A1 - Malz, Frank A1 - Pauli, Jutta A1 - Jäger, Christian A1 - Reinsch, Stefan A1 - Scholz, G. T1 - Aluminum speciation and thermal evolution of aluminas resulting from modified Yoldas sols N2 - Aluminas resulting from sols prepared via a modified Yoldas procedure were studied with differential thermal analysis (DTA), differential thermal gravimetrie (DTG), 27Al nuclear magnetic resonance (27Al MAS NMR) and X-ray diffraction (XRD) concerning their thermal properties, aluminum speciation and phase content. Hydrolysis of aluminum-sec-butoxide in aluminum nitrate solutions allowed to prepare stable sols with varying NO3-/Al molar ratios, solids contents and pH values. Resulting sols contained different aluminum species including also Al13 polycations. Sol preparation conditions also determined aluminum speciation in solid products obtained after thermal treatments of gels obtained from these sols. Al13 polycations and AlO5 species were found to play an important role for thermally induced transformation from amorphous products via eta-Al2O3 to alpha-Al2O3. Intermediately formed eta-Al2O3 promotes the phase transformation to alpha-Al2O3. KW - Alumina KW - Modified Yoldas sols KW - 27Al nuclear magnetic resonance KW - Differential thermal analysis KW - X-ray diffraction PY - 2007 DO - https://doi.org/10.1016/j.jssc.2007.06.018 SN - 0022-4596 SN - 1095-726X VL - 180 IS - 9 SP - 2409 EP - 2419 PB - Elsevier CY - San Diego, Calif. AN - OPUS4-16189 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - 13C{31P} REDOR solid state NMR proves the organic-mineral interface in bone is stabilized by polysaccharides T2 - GDCh-Fachgruppenmeeting 2007 CY - Göttingen, Germany DA - 2007-09-26 PY - 2007 AN - OPUS4-16388 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Probing the structure of bone: understanding the organic-mineral and drug molecule interactions T2 - 5th Alpine Conference on Solid-State NMR CY - Chamonix, France DA - 2007-09-09 PY - 2007 AN - OPUS4-16389 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Malz, Frank A1 - Aguiar, H. A1 - Solla, E.L. A1 - Serra, J. A1 - González, P. A1 - León, B. A1 - Jäger, Christian T1 - Combined structural investigations of bioactive silicate glasses N2 - The results of a combined structural characterisation (XRD, IR, NMR, SEM, TEM) of a phosphate containing Mg-Ca silicate and a phosphate containing Na-Ca silicate glass samples are presented. The structural results are also compared with in vitro tests carried out in simulated body fluids for checking bioactivity. KW - Bioactive glasses KW - Silicate glasses KW - NMR KW - Raman KW - TEM PY - 2008 SN - 1013-9826 VL - 361-363 SP - 257 EP - 260 PB - Trans Tech Publ. CY - Aedermannsdorf AN - OPUS4-16572 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Solla, E.L. A1 - Malz, Frank A1 - González, P. A1 - Serra, J. A1 - Jäger, Christian A1 - León, B. T1 - The Role of Si Substitution into Hydroxyapatite Coatings N2 - Silicon substituted Hydroxyapatite coatings were prepared by Pulsed Laser Deposition from targets made of mixtures of Hydroxyapatite with Si powder at different concentrations. The properties of the Si-HA coatings with several degrees of Si substitution were analyzed by different techniques such as FTIR, XRD, XPS and solid-state NMR. It was found that the Si incorporation causes an amorphization of the structure together with a loss of carbonate groups. Furthermore, the Si atoms are incorporated in the form of SiO4 4- groups, and H(PO4)2- appears as the predominant phosphate group. KW - Si substituted hydroxyapatite KW - Bioactive coatings KW - Solid state NMR KW - Pulsed laser deposition PY - 2008 SN - 1013-9826 VL - 361-363 SP - 175 EP - 178 PB - Trans Tech Publ. CY - Aedermannsdorf AN - OPUS4-16576 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wettmarshausen, Sascha A1 - Min, Hyegeun A1 - Unger, Wolfgang A1 - Jäger, Christian A1 - Hidde, Gundula A1 - Friedrich, Jörg Florian T1 - Significance of hydrogen-deuterium exchange at polyolefin surfaces on exposure to ammonia low-pressure plasma N2 - Since more than 40 years ammonia plasma exposure of polyolefins is used for introduction of primary amino groups. The selectivity of this reaction and the yield in primary amino groups was found to be low. Here, a prominent side-reactions of this process was investigated, the hydrogenation by NH3 plasma. For identification of hydrogenation ammonia (NH3) and deuterated ammonia (ND3) were exposed to Polyethylene (h-PE) and fully deuterated polyethylene (d-PE) as well as hexatriacontane (h-HTC) and fully deuterated hexatriacontane (d-HTC) as low-molecular weight model for PE. H–D exchange was assumed and detected by Time-of-Flight Secondary Ion Mass Spectrometry (ToF–SIMS), X-ray Photoelectron Spectroscopy (XPS), Attenuated Total Reflectance (ATR-FTIR) and 1H and 2H Nuclear magnetic Resonance. Results show a significant H–D exchange within the sampling depth of ATR (2.5 µm). However, N- and NH2 introduction was limited to the topmost surface as shown by SIMS and XPS (a few nanometers). KW - Deuterated ammonia KW - Ammonia plasma KW - Deuterated polyolefins KW - Hexatriacontane KW - H-D exchange PY - 2011 DO - https://doi.org/10.1007/s11090-011-9304-5 SN - 0272-4324 VL - 31 IS - 4 SP - 551 EP - 572 PB - Plenum Publ. Corp. CY - New York, NY, USA AN - OPUS4-24178 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Towards nature and quantification of acid sites of amorphous silicia alumina using NMR T2 - Kooperationstreffen, Sasol GmbH CY - Brunsbüttel, Germany DA - 2011-09-27 PY - 2011 AN - OPUS4-24385 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kosslick, H. A1 - Pitsch, I. A1 - Deutsch, J. A1 - Pohl, M.-M. A1 - Schulz, A. A1 - Vu, A.T. A1 - Nguyen, D.T. A1 - Frunza, L. A1 - Jäger, Christian T1 - Improved large mesoporous ordered molecular sieves - Stabilization and acid/base functionalization N2 - The preparation of nanoporous materials with enhanced stability using an improved synthesis route using reactive inorganic silica and alumina species is reported. This way improved mesoporous molecular sieves were obtained. The synthesized aluminum substituted mesoporous molecular materials (Al-MMS) contain very large pores of 50–200 Å size combined with an improved pore wall thickness. Increased wall thickness and Al substitution lead to an improved chemical stability against alkaline solution. The textural, structural and acid properties are investigated by physico-chemical methods. The catalytic performance acidic materials was tested in the benzoylation reaction; amino functionalized materials were studied in the base catalyzed Michael addition. KW - Nanoporous molecular sieve KW - Al substitution KW - Stability KW - Synthesis KW - Acidity KW - Catalysis PY - 2010 DO - https://doi.org/10.1016/j.cattod.2010.03.005 SN - 0920-5861 VL - 152 IS - 1-4 SP - 54 EP - 60 PB - Elsevier CY - Amsterdam AN - OPUS4-23960 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Barheine, Sabrina A1 - Hayakawa, S. A1 - Jäger, Christian A1 - Shirosaki, Y. A1 - Osaka, A. T1 - Effect of disordered structure of boron-containing calcium phosphates on their in vitro biodegradability N2 - This study proposes a new guideline for designing biodegradable apatite ceramics. Boron-containing hydroxyapatite (BHAp) particles were prepared by a high-temperature solid-state reaction processing method and were characterized in terms of their chemical composition, apatite lattice defects and in vitro biodegradability. Solid-state nuclear magnetic resonance analysis showed that boron-incorporation into hydroxyapatite (HAp) derived by thermo-chemical reactions between borate and calcium phosphate phases led to disordered phases (BCaP) of a CaO–P2O5–B2O3–OH system covering the crystalline HAp core. X-ray diffraction analysis indicated that the BCaP phase must consist mainly of a crystalline oxyboroapatite (OBAp) phase. An in vitro biodegradability test showed that BHAp degraded quicker than HAp or ß-tricalcium phosphate. The biodegradability of BHAp particles can be controlled by boron incorporation into a HAp lattice leading to the formation of a disordered OBAp phase. KW - Boron KW - Hydroxyapatite KW - Calcium phosphate KW - NMR KW - Biodegradability KW - Disorder KW - Oxyboboapatite PY - 2011 DO - https://doi.org/10.1111/j.1551-2916.2011.04400.x SN - 0002-7820 SN - 1551-2916 VL - 94 IS - 8 SP - 2656 EP - 2662 PB - Blackwell Publishing CY - Malden AN - OPUS4-26244 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - König, R. A1 - Scholz, G. A1 - Veiczi, M. A1 - Jäger, Christian A1 - Troyanov, S.I. A1 - Kemnitz, E. T1 - New crystalline aluminium alkoxide oxide fluorides: evidence of the mechanism of the fluorolytic sol-gel reaction N2 - This study reports three new crystalline aluminum isopropoxide oxide fluorides with molar ratios of Al:F equal to 1:1 and 1:1.25. These are the first three representatives isolated without the incorporation of external donor molecules. Compound 1 Al4F4(µ4-O)(µ-O'Pr)5[H(O'Pr)2] contains a tetranuclear unit consisting of two different five fold coordinated AlFO4-units, with F exclusively in the terminal position. Compound 2, Al4F4(µ4-O)(µ-O'Pr)5[H(O'Pr)2]·Al5F5(µ5-O)(µ-O'Pr)8, contains both a tetranuclear unit (as in 1) and a pentanuclear Al-unit. Al-atoms in the latter are five- and six fold coordinated. Compound 3, Al16F20(µ4-O)4(µ-O'Pr)20·2('PrOH), exhibits a slightly higher fluorination degree and contains an oligomeric chain of four F-linked tetranuclear Al-units. In addition to X-ray structure analysis, compound 1 was characterized by different solid state MAS NMR techniques, including 27Al triple quantum MAS NMR and 1H, 1H→13C CP, 19F and 27Al MAS NMR. On the basis of the collected data, a reliable decomposition of 27Al single pulse MAS NMR spectra and an unambiguous assignment of the resonances to the respective structural AlFO4-units are given. The new crystalline aluminum isopropoxide oxide fluorides are direct evidence of the fluorolytic sol–gel mechanism previously discussed. KW - Aluminium fluorine KW - MAS NMR KW - Qudrupolar nuclei KW - Crystalline aluminium isopropoxide fluoride PY - 2011 DO - https://doi.org/10.1039/c1dt10514k SN - 1477-9226 SN - 1477-9234 SN - 1364-5447 VL - 40 IS - 34 SP - 8701 EP - 8710 PB - RSC CY - Cambridge AN - OPUS4-26245 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hemmann, F. A1 - Scholz, G. A1 - Scheurell, K. A1 - Kemnitz, E. A1 - Jäger, Christian T1 - Time-optimized 15N qNMR determination of Lewis and Brønsted site concentrations and chemical bonding of pyridine at Brønsted sites in amorphous aluminium hydroxide fluoride N2 - Time-optimized 15N quantitative NMR (qNMR) is described for the precise determination of Lewis and Brønsted site concentrations per gram catalyst, enabling a measurement time reduction of more than a factor of 10. The proof-of-principle is demonstrated for amorphous aluminum hydroxide fluorides with their tunable Lewis to Brønsted functionalities and relevance to highly active and selective heterogeneous catalysis using pyridine as a widely accepted probe molecule for Lewis and Brønsted sites. Two different Lewis centers were found, and reliable site concentrations down to the micromole per gram region can be determined. Furthermore, 1H{15N} REDOR NMR for the acid proton at the Brønsted site yields a distance of the 15N atom of bonded pyridine to this acid proton of (0.112 ± 0.002) nm, such that fast motion/diffusion of the Brønsted site-bonded pyridine at the surface can be excluded. KW - Catalysis KW - Lewis/Brønsted acid sites KW - Acid site concentration KW - Pyridine KW - Quantitative NMR KW - 15N KW - REDOR PY - 2012 DO - https://doi.org/10.1021/jp212045w SN - 1932-7447 SN - 1089-5639 VL - 116 IS - 19 SP - 10580 EP - 10585 PB - Soc. CY - Washington, DC AN - OPUS4-27724 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Debatin, F. A1 - Behrens, K. A1 - Weber, J. A1 - Baburin, I. A. A1 - Thomas, A. A1 - Schmidt, J. A1 - Senkovska, I. A1 - Kaskel, S. A1 - Kelling, A. A1 - Hedin, N. A1 - Bacsik, Z. A1 - Leoni, S. A1 - Seifert, G. A1 - Jäger, Christian A1 - Günter, C. A1 - Schilde, U. A1 - Friedrich, A. A1 - Holdt, H.-J. T1 - An isoreticular family of microporous metal-organic frameworks based on zinc and 2-substituted imidazolate-4-amide-5-imidate: syntheses, structures and properties N2 - We report on a new series of isoreticular frameworks based on zinc and 2-substituted imidazolate-4-amide-5-imidate (IFP-1–4, IFP=imidazolate framework Potsdam) that form one-dimensional, microporous hexagonal channels. Varying R in the 2-substitued linker (R=Me (IFP-1), Cl (IFP-2), Br (IFP-3), Et (IFP-4)) allowed the channel diameter (4.0–1.7 Å), the polarisability and functionality of the channel walls to be tuned. Frameworks IFP-2, IFP-3 and IFP-4 are isostructural to previously reported IFP-1. The structures of IFP-2 and IFP-3 were solved by X-ray crystallographic analyses. The structure of IFP-4 was determined by a combination of PXRD and structure modelling and was confirmed by IR spectroscopy and 1H MAS and 13C CP-MAS NMR spectroscopy. All IFPs showed high thermal stability (345–400°C); IFP-1 and IFP-4 were stable in boiling water for 7 d. A detailed porosity analysis was performed on the basis of adsorption measurements by using various gases. The potential of the materials to undergo specific interactions with CO2 was investigated by measuring the isosteric heats of adsorption. The capacity to adsorb CH4 (at 298 K), CO2 (at 298 K) and H2 (at 77 K) at high pressure were also investigated. In situ IR spectroscopy showed that CO2 is physisorbed on IFP-1–4 under dry conditions and that both CO2 and H2O are physisorbed on IFP-1 under moist conditions. KW - Adsorption KW - Metal-organic frameworks KW - Microporous materials KW - N,O ligands KW - Zinc PY - 2012 DO - https://doi.org/10.1002/chem.201200889 SN - 0947-6539 SN - 1521-3765 VL - 18 IS - 37 SP - 11630 EP - 11640 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-27725 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hayakawa, S. A1 - Kanaya, T. A1 - Tsuru, K. A1 - Shirosaki, Y. A1 - Osaka, A. A1 - Fujii, E. A1 - Kawabata, K. A1 - Gasqueres, G. A1 - Bonhomme, C. A1 - Babonneau, F. A1 - Jäger, Christian A1 - Kleebe, H.-J. T1 - Heterogeneous structure and in vitro degradation behavior of wet-chemically derived nanocrystalline silicon-containing hydroxyapatite particles N2 - Nanocrystalline hydroxyapatite (HAp) and silicon-containing hydroxyapatite (SiHAp) particles were synthesized by a wet-chemical procedure and their heterogeneous structures involving a disordered phase were analyzed in detail by X-ray diffractometry (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and solid-state magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. The effects of heterogeneous structure on in vitro biodegradability and the biologically active Ca(II)- and Si(IV)-releasing property of SiHAp particles were discussed. The 29Si NMR analysis revealed that the Si(IV) was incorporated in the HAp lattice in the form of Q0 (SiO4-4 or HSiO3-4) species, accompanied by the formation of condensed silicate units outside the HAp lattice structure, where the fraction and amount of Q0 species in the HAp lattice depends on the Si content. The 31P and 1H NMR results agreed well with the XRD, TEM and FTIR results. NMR quantitative analysis results were explained by using a core–shell model assuming a simplified hexagonal shape of HAp covered with a disordered layer, where Si(IV) in Q0 was incorporated in the HAp lattice and a disordered phase consisted of hydrated calcium phosphates involving polymeric silicate species and carbonate anions. With the increase in the Si content in the HAp lattice, the in vitro degradation rate of the SiHAps increased, while their crystallite size stayed nearly unchanged. The biologically active Ca(II)- and Si(IV)-releasing ability of the SiHAps was remarkably enhanced at the initial stage of reactions by an increase in the amount of Si(IV) incorporated in the HAp lattice but also by an increase of the amount of polymeric silicate species incorporated in the disordered phase. KW - Silicate KW - Calcium phosphate KW - Hydroxyapatite KW - Degradation KW - Apatite formation PY - 2013 DO - https://doi.org/10.1016/j.actbio.2012.08.024 SN - 1742-7061 VL - 9 IS - 1 SP - 4856 EP - 4867 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-27319 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mohamed, Zeinab A1 - Krüger, Simone A1 - Hidde, Gundula A1 - Schimanski, A. A1 - Jäger, Christian A1 - Friedrich, Jörg Florian T1 - Deposition of thick polymer or inorganic layers with flame-retardant properties by combination of plasma and spray processes N2 - Mixtures of hexamethyldisiloxane (HMDSO) and oxygen have been used for deposition of SiO2-like layers by plasma polymerization under low-pressure conditions onto polyethylene and polystyrene used as basecoat. Water glass was cast onto these 0.5 µm plasma thick siloxane-like layers with a thickness of 5 to 40 µm. The adhesion of these bilayer systems and their flame resistance were tested. The effect of different plasma parameters such as monomer/gas ratio, pressure and power input into the discharge on the deposition rate and the composition of the formed layers was studied. Characterization and chemical composition of the formed films were performed using infrared, X-ray photoelectron and solid state nuclear magnetic resonance spectroscopy. Peel strengths of composites were measured and the locus of peel front propagation was detected. Thermal properties of composites were analyzed by thermo-gravimetric analysis. Finally, the fire-retardant properties of thick coated polymers were determined by exposure to flames and the behavior of coatings on the polymers during flaming was observed visually. KW - Plasma polymerization KW - Hexamethyldisiloxane plasma polymer KW - Polystyrene KW - Polyethylene KW - Flame retardancy PY - 2013 DO - https://doi.org/10.1016/j.surfcoat.2013.04.039 SN - 0257-8972 VL - 228 SP - 266 EP - 274 PB - Elsevier B.V. CY - Lausanne AN - OPUS4-28735 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Diakité, M. A1 - Paul, Andrea A1 - Jäger, Christian A1 - Pielert, J. A1 - Mumme, J. T1 - Chemical and morphological changes in hydrochars derived from microcrystalline cellulose and investigated by chromatographic, spectroscopic and adsorption techniques N2 - Hydrothermal carbonization (HTC) can be used for converting the biomass into a carbon-rich material, whose application as a fuel requires higher heating value, whereas soil amendment needs stable carbon. This work was focused on the characterization of hydrochars derived from microcrystalline cellulose. The chars were investigated using elemental analysis, Brunauer–Emmett–Teller technique, nuclear magnetic resonance spectroscopy, Raman, Fourier transform infrared, and electron spin resonance spectroscopy. Severity in temperature between 230 and 270 °C with reaction times between 2 and 10 h only affect the carbon content moderately. The results show that aromatization of HTC chars correlates well with temperature, which was further supported by the increase of organic radicals with decreasing g values at higher temperatures. Based on these results, the energetic use of chars favors mild HTC (T < 230 °C and t ≤ 6 h), while the soil amendement favors serve conditions (T ≥ 230 °C, and t > 6 h). KW - Hydrothermal carbonization KW - Hydrochar KW - Microcrystalline cellulose KW - NMR-spectroscopy KW - ATR-FTIR-spectroscopy PY - 2013 DO - https://doi.org/10.1016/j.biortech.2013.09.129 SN - 0960-8524 SN - 1873-2976 VL - 150 SP - 98 EP - 105 PB - Elsevier Ltd. CY - Barking, Essex AN - OPUS4-29824 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian A1 - Pauli, Jutta A1 - Berger, Georg A1 - Spitzer, Andrea T1 - Entwicklung neuartiger Knochenersatzwerkstoffe und strukturelle Charakterisierung mittels der 31P-NMR-Spektroskopie T2 - Tagung "Tag der Chemie" CY - Berlin, Deutschland DA - 2002-12-04 PY - 2002 AN - OPUS4-1900 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fichera, Mario Augusto A1 - Jäger, Christian T1 - A solid state NMR study of the pyrolysis and thermo-oxidative decomposition products of flame retardant HIPS T2 - ANAKON 2007 GDCh Fachgruppe Analytische Chemie CY - Jena, Germany DA - 2007-03-27 PY - 2007 AN - OPUS4-14657 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - De Souza, C.M.G. A1 - Greiser, Sebastian A1 - Garcia, E. A1 - Quarcioni, V.A. A1 - Jäger, Christian ED - Bílek, V. ED - Kersner, Z. T1 - Evaluation of pozzolanic reactivity of calcined kaolinite N2 - The need to improve the sustainability and the need for innovation in the cement industry has brought to light the practice of using additives to the cement in order to decrease CO2 emissions in industrial plants and increase the quality of cement in terms of durability and performance. Currently some additives have been employed as granulated blast furnace slag, limestone and pozzolan. The additives give mortar and concrete larger energy efficiency, gain in durability and resistance, contributing to buildings with slender structures and cheaper and durable maintenance. Besides natural pozzolan can be used artificial ones, as calcined clays, and over a range of amorphous aluminates and silicates waste, with highly reactive function as a binder material in the presence of water and calcium hydroxide. Calcined kaolinite clays were characterized using various techniques such as XRD, thermal analysis, and NMR observing 27Al and 29Si nuclei. The results showed that there is a structural modification of the samples, from crystalline to amorphous phases with the increasing of temperature in the calcination process. There is an improving in the reactivity of calcined clays by the range of 600ºC to 750ºC temperature in the reaction with calcium oxide, according to data from Chapelle test, indicating the possibility of using them as additives for cement and confirming their pozzolanic potential. T2 - NTCC2014 - International conference on non-traditional cement and concrete CY - Brno, Czech Republic DA - 16.06.2014 KW - Kaolin KW - Pozzolan KW - Calcined clays KW - Cement additive PY - 2014 SN - 978-80-214-4867-4 SP - 225 EP - 228 PB - Novpress AN - OPUS4-31225 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Greiser, Sebastian A1 - Hunger, M. A1 - Jäger, Christian T1 - 29Si{27Al} TRAPDOR MAS NMR to distinguish Qn(mAl) sites in aluminosilicates. Test case: Faujasite-type zeolites N2 - 29Si{27Al} TRAPDOR MAS NMR was applied to two faujasite-type zeolites with Si/Al ratios of 1.3 (Na-X) and 2.7 (Na-Y). The aim of this test study is to show that different Q4(mAl) sites (m=4,3,2,1) can be distinguished by differently strong TRAPDOR effects (ΔS/S0). Indeed, it was found that the TRAPDOR effect depends on the number m of AlO4 units connected to the Q4 silicon tetrahedrons. For Na-X, the measured ΔS/S0 values are 1:0.81:0.56 for Q4(4Al), Q4(3Al) and Q4(2Al), respectively (normalized to Q4(4Al)). The corresponding ΔS/S0 values are the same for Na-Y within the error bars, although the silicon sites are different: Q4(3Al), Q4(2Al) and Q4(1Al) and now normalized to Q4(3Al) as no Q4(4Al) is present. Nevertheless, the proposed method opens up the possibility to distinguish overlapping 29Si NMR signals of the Qn(mAl) sites in amorphous materials as the main goal of these investigations. KW - Solid-state NMR KW - 29Si{27Al} TRAPDOR MAS NMR KW - Q4(mAl) sites KW - Faujasite-type zeolites KW - Aluminosilicates PY - 2016 DO - https://doi.org/10.1016/j.ssnmr.2016.10.004 SN - 0926-2040 SN - 1527-3326 VL - 80 SP - 6 EP - 10 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-38718 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - De Souza, C.M.G. A1 - Greiser, Sebastian A1 - Garcia, E. A1 - Quarcioni, V.A. A1 - Jäger, Christian T1 - Evaluation of pozzolanic reactivity of calcined kaolinite N2 - The need to improve the sustainability and the need for innovation in the cement industry has brought to light the practice of using additives to the cement in order to decrease CO2 emissions in industrial plants and increase the quality of cement in terms of durability and performance. Currently some additives have been employed as granulated blast furnace slag, limestone and pozzolan. The additives give mortar and concrete larger energy efficiency, gain in durability and resistance, contributing to buildings with slender structures and cheaper and durable maintenance. Besides natural pozzolan can be used artificial ones, as calcined clays, and over a range of amorphous aluminates and silicates waste, with highly reactive function as a binder material in the presence of water and calcium hydroxide. Calcined kaolinite clays were characterized using various techniques such as XRD, thermal analysis, and NMR observing 27Al and 29Si nuclei. The results showed that there is a structural modification of the samples, from crystalline to amorphous phases with the increasing of temperature in the calcination process. There is an improving in the reactivity of calcined clays by the range of 600ºC to 750ºC temperature in the reaction with calcium oxide, according to data from Chapelle test, indicating the possibility of using them as additives for cement and confirming their pozzolanic potential. KW - Kaolin KW - Pozzolan KW - Calcined clays KW - Cement additive PY - 2014 DO - https://doi.org/10.15623/ijret.2014.0325033 SN - 2321-7308 SN - 2319-1163 VL - 3 IS - Special Issue 13 SP - 209 EP - 213 PB - eSAT Publishing House CY - Kothapatnam AN - OPUS4-38719 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sut, Aleksandra A1 - Greiser, Sebastian A1 - Jäger, Christian A1 - Schartel, Bernhard T1 - Interactions in multicomponent flame-retardant polymers: Solid-state NMR identifying the chemistry behind it N2 - Distinct approaches are used to reduce the fire risks of polymers, a key issue for many industrial applications. Among the variety of approaches, the use of synergy in halogen-free multicomponent systems is one of the most auspicious. To optimize the composition of such flame-retardant systems it is essential to understand the mechanisms and the corresponding chemistry in the condensed phase. In this work different methods are used, including cone calorimeter, thermogravimetry (TG), and TG-FTIR, with the main focus on the solid-state NMR analysis of the solid residues. The structural changes in the condensed phase of two thermoplastic elastomer systems based on copolymer styrene-ethylene-butadiene-styrene (TPE-S) were investigated: TPE-S/aluminium diethylphosphinate (AlPi)/magnesium hydroxide (MH) and TPE-S/AlPi/zinc borate (ZB)/poly(phenylene oxide) (PPO). Strong flame inhibition is synergistically combined with protective layer formation. 13C-, 27Al-, 11B- and 31P MAS NMR (magic angle spinning nuclear magnetic resonance) experiments using direct excitation with a single pulse and 1H–31P cross-polarization (CP) were carried out as well as double resonance techniques. Magnesium phosphates were formed during the pyrolysis of TPE-S/AlPi/MH, while for the system TPE-S/AlPi/ZB/PPO zinc phosphates and borophosphates were observed. Thus, the chemistry behind the chemical interaction was characterized unambiguously for the investigated systems. KW - Synergy KW - Solid-state NMR KW - Flame retardancy KW - SEBS KW - Aluminium diethylphosphinate KW - Magnesium hydroxide KW - Zinc borate KW - Poly(phenylene) oxide PY - 2015 DO - https://doi.org/10.1016/j.polymdegradstab.2015.08.018 SN - 0141-3910 SN - 1873-2321 VL - 121 SP - 116 EP - 125 PB - Applied Science Publ. CY - London AN - OPUS4-34306 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - da Silva, D.A. A1 - Greiser, Sebastian A1 - Contro, J. A1 - Medeiros, V.L. A1 - Nery, J.G. A1 - Jäger, Christian T1 - 1H, 29Si and 119Sn double and triple resonance NMR spectroscopy of the small-pore framework sodium stannosilicate Na2SnSi3O9⋅2H2O N2 - The small-pore framework sodium stannosilicate AV-10, chemical composition Na2SnSi3O9⋅2H2O and known crystallographic structure, was synthesized by hydrothermal crystallization. This stannosilicate is built up of a three-dimensional network of corner-shared SiO4 tetrahedra and SnO6 octahedra. The SnO6 sites are linked to six SiO4 tetrahedra (Sn(6Si)) while each of the two crystallographically different SiO4 units are connected to two SnO6 and SiO4 units (Si(2Si,2Sn)). This material was used as model compound for developing a solid-state MAS NMR strategy aimed on the challenges and possibilities for structural studies, particularly considering the short and medium range order to verify the connectivity of SiO4 and SnO6 of such compounds despite the low natural abundances of 4.68% for 29Si and 8.59% for 119Sn nuclei as a real challenge. 29Si{119Sn} and 119Sn{29Si} REDOR (Rotational-Echo Double-Resonance) NMR measurements after 1H cross-polarization (CP) were carried out. The REDOR curves show a significant change after the “normal” quadratic short time evolution from which both (i) the shortest internuclear 29Si – 119Sn distances (and vice versa) and (ii) the number of corner-sharing SiO4 tetrahedra around the SnO6 octahedra (and vice versa) can be obtained. Based on these data, optimized 29Si {119Sn} and 119Sn{29Si} REPT-HMQC (Recoupled Polarization Transfer-Heteronuclear Multiple-Quantum Correlation, again after 1H CP) experiments were implemented, which directly show those heterogroup connectivity as correlation peaks in a 2D spectrum. This information was also obtained using 2D29Si{119Sn}-J-Coupling NMR experiments. Furthermore, 2D29Si INADEQUATE NMR experiments are also feasible, showing the connectivity of SiO4 tetrahedra. The combination of REDOR, REPT-HMQC, J-Coupling and INADEQUATE experiments yielded a complete analysis of the short and medium range structure of this microporous stannosilicate, in agreement with the previously published structure obtained Ab Initio from powder X-Ray diffraction data (XRD). KW - Stannosilicates KW - REDOR KW - REPT-HMQC KW - INADEQUATE PY - 2020 DO - https://doi.org/10.1016/j.ssnmr.2020.101661 SN - 0926-2040 VL - 107 SP - 101661 PB - Elsevier Inc. AN - OPUS4-50710 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sut, Aleksandra A1 - Greiser, Sebastian A1 - Jäger, Christian A1 - Schartel, Bernhard T1 - Synergy in flame-retarded epoxy resin - Identification of chemical interactions by solid-state NMR N2 - The potential synergists aluminium diethylphosphinate (AlPi), boehmite (AlO(OH)) and melamine polyphosphate (MPP) were compared in flame-retardant epoxy resin (EP)/melamine poly(magnesium phosphate) (S600). The pyrolysis, the fire behaviour as well as the chemical interactions in the gas and condensed phases were investigated by various methods. Flammability was investigated by cone calorimeter and oxygen index (OI). The thermal and thermo-oxidative decomposition were studied by thermogravimetric analysis coupled with FTIR spectrometer. The special focus was on the Investigation of structural changes in the condensed phase via solid-state NMR of 27Al and 31P nuclei. By the comparison of epoxy resin with only one additive or with S600 in combination with AlPi, AlO(OH) or MPP, it was possible to calculate the synergy index. The best performance in terms of fire behaviour was observed for EP/S600/MPP with a PHRR (Peak heat release rate) of 208 kW m-2 due to slight synergy. In the case of THE (total heat evolved), clear synergy occurred for EP/S600/AlPi and EP/S600/AlO(OH). By solid-state NMR, different phosphates and aluminates were identified, indicating the chemical interactions between S600 and AlPi, AlO(OH) or MPP. The systematic multi-methodical approach yielded insight into the synergistic effects in the flame-retarded epoxy resin. KW - Synergy KW - Epoxy resin KW - Flame retardancy KW - Melamine poly(magnesium phosphate) KW - Solid-state NMR PY - 2017 DO - https://doi.org/10.1007/s10973-016-5934-4 SN - 1388-6150 SN - 1588-2926 VL - 128 IS - 1 SP - 141 EP - 153 PB - Springer AN - OPUS4-39298 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sut, Aleksandra A1 - Greiser, Sebastian A1 - Jäger, Christian A1 - Schartel, Bernhard T1 - Aluminium diethylphosphinate versus ammonium polyphosphate: A comprehensive comparison of the chemical interactions during pyrolysis in flame-retarded polyolefine/poly(phenylene oxide) N2 - A systematic comparison of chemical interactions and fire behaviour is presented for the thermoplas-tic elastomer (block copolymer styrene-ethylene-butadiene-styrene) (TPE-S)/diethyl- and methylvinylsiloxane (Si)/poly(phenylene oxide) (PPO), flame-retarded with aluminium diethylphosphinate (AlPi)and with ammonium polyphosphate (APP), respectively. TPE-S/APP/Si/PPO performed better in the conecalorimeter test (reduction in peak heat release rate from 2042 to 475 kW m−2), but TPE-S/AlPi/Si/PPO inthe flammability tests (oxygen index (OI) and UL 94). This difference was caused by the different modes ofaction of APP (more in the condensed phase) and AlPi (mainly in the gas phase). Thermogravimetry cou-pled with Fourier transform infrared spectroscopy (TG-FTIR) was used to analyse the mass loss and theevolved gas products, while a Linkam hot-stage cell to investigate the decomposition in the condensedphase. Moreover, a detailed analysis of the fire residues was done using solid-state NMR.13C MAS NMRshowed that both flame-retarded compositions form graphite-like amorphous carbonaceous char, orig-inating from PPO.31P MAS NMR and29Si MAS NMR delivered important information about interactionbetween phosphorus and the siloxane. For TPE-S/AlPi/Si/PPO aluminium phosphate and silicon dioxideoccurred, while also silicophosphate was produced in TPE-S/APP/Si/PPO. The direct comparison of two ofthe most prominent halogen-free flame retardants containing phosphorus delivered meaningful insightsinto the modes of action and molecular mechanisms controlling flame retardancy. KW - Aluminium diethylphosphinate KW - Ammonium polyphosphate KW - Flame retardancy KW - Solid-state NMR KW - SEBS PY - 2016 SN - 0040-6031 SN - 1872-762X VL - 640 SP - 74 EP - 84 PB - Elsevier AN - OPUS4-37802 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hennig, Andreas A1 - Dietrich, Paul A1 - Hemmann, Felix A1 - Thiele, T. A1 - Borcherding, H. A1 - Hoffmann, Angelika A1 - Schedler, U. A1 - Jäger, Christian A1 - Resch-Genger, Ute A1 - Unger, Wolfgang T1 - En route to traceable reference standards for surface group quantifications by XPS, NMR and fluorescence spectroscopy N2 - The fluorine content of polymer particles labelled with 2,2,2-trifluoroethylamine was reliably quantified with overlapping sensitivity ranges by XPS and solid-state NMR. This provides a first step towards reference materials for the metrological traceability of surface group quantifications. The extension of this concept to fluorescence spectroscopy is illustrated. KW - Polymer beads KW - Poly(acrylic acid)-grafted particles KW - XPS KW - SEM KW - Surface analysis KW - Fluorescent dye labeling KW - NMR PY - 2015 DO - https://doi.org/10.1039/c4an02248c SN - 0003-2654 SN - 1364-5528 VL - 140 IS - 6 SP - 1804 EP - 1808 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-32794 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jäger, Christian T1 - Comparison of 19F qNMR, absolute fluorescence, and absorption measurement of dye concentrations in fluorescent PS particles T2 - 53rd Experimental Nuclear Magnetic Resonance Conference CY - Miami, FL, USA DA - 2012-04-15 PY - 2012 AN - OPUS4-25718 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fichera, Mario Augusto A1 - Braun, Ulrike A1 - Schartel, Bernhard A1 - Sturm, Heinz A1 - Knoll, Uta A1 - Jäger, Christian T1 - Solid-state NMR investigations of the pyrolysis and thermo-oxidative decomposition products of a polystyrene/red phosphorus/magnesium hydroxide system N2 - Thermal, thermo-oxidative and fire residues of high impact polystyrene/magnesium hydroxide/red phosphorus (HIPS/Mg(OH)2/Pr) are investigated by solid-state NMR and compared with the results for the binary subsystem Mg(OH)2/Pr. The influences of oxygen, nitrogen and temperature are discussed. For a thermal decomposition and pyrolysis during combustion, the main pyrolysis of HIPS takes place while the remaining residue is a rather intact polymer, with a major share of the embedded Pr still present. Subsequently, mainly amorphous phosphates and a slight amount of crystalline Mg3(PO4)2 and Mg2P2O7 are formed at the highest temperatures. Only with increasing mass loss does the remaining polystyrene structure decompose and graphitic structures occur. The influence of oxygen on the decomposition mechanism is most obvious for the binary system Mg(OH)2/Pr. Pr vanishes more rapidly and crystalline, oxygen-rich magnesium phosphates are formed. In HIPS/Mg(OH)2/Pr systems the polymer acts as a barrier to reaction by the embedded particles, so that major characteristics of an anaerobic decomposition are found. Significant amounts of phosphorus are retained in the condensed phase through a reaction of Pr with Mg(OH)2 to mostly amorphous phosphates. This formation of amorphous inorganic magnesium phosphates can act as an additional physical barrier. This study outlines some advanced approaches for controlling the condensed-phase mechanisms of phosphorus and underlines that solid-state NMR is a most powerful tool for investigating the organic and inorganic residues. KW - HIPS KW - Red phosphorus KW - Magnesium hydroxide KW - Solid-state NMR KW - Flame retarded polymers PY - 2007 SN - 0165-2370 SN - 1873-250X VL - 78 IS - 2 SP - 378 EP - 386 PB - Elsevier CY - Amsterdam AN - OPUS4-14517 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Seto, J. A1 - Ma, Y. A1 - Davis, S.A. A1 - Meldrum, F. A1 - Gourrier, A. A1 - Kim, Y.-Y. A1 - Schilde, U. A1 - Sztucki, M. A1 - Burghammer, M. A1 - Maltsev, Sergey A1 - Jäger, Christian A1 - Cölfen, H. T1 - Structure-property relationships of a biological mesocrystal in the adult sea urchin spine N2 - Structuring over many length scales is a design strategy widely used in Nature to create materials with unique functional properties. We here present a comprehensive analysis of an adult sea urchin spine, and in revealing a complex, hierarchical structure, show how Nature fabricates a material which diffracts as a single crystal of calcite and yet fractures as a glassy material. Each spine comprises a highly oriented array of Mg-calcite nanocrystals in which amorphous regions and macromolecules are embedded. It is postulated that this mesocrystalline structure forms via the crystallization of a dense array of amorphous calcium carbonate (ACC) precursor particles. A residual surface layer of ACC and/or macromolecules remains around the nanoparticle units which creates the mesocrystal structure and contributes to the conchoidal fracture behavior. Nature’s demonstration of how crystallization of an amorphous precursor phase can create a crystalline material with remarkable properties therefore provides inspiration for a novel approach to the design and synthesis of synthetic composite materials. KW - Calcium carbonate biomineralization KW - Echinoderm skeleton KW - Hierarchical structuring KW - Mesocrystal KW - Skeletal elements PY - 2012 DO - https://doi.org/10.1073/pnas.1109243109 SN - 0027-8424 SN - 1091-6490 VL - 109 IS - 10 SP - 3699 EP - 3704 PB - National Academy of Sciences CY - Washington, DC AN - OPUS4-27726 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kowalke, J. A1 - Arnold, C. A1 - Ponomarev, I. A1 - Jäger, Christian A1 - Kroll, P. A1 - Brendler, E. A1 - Kroke, E. T1 - Structural Insight into Layered Silicon Hydrogen Phosphates Containing [SiO6] Octahedra Prepared by Different Reaction Routes N2 - The layered silicophosphate Si(HPO4)(2) was prepared via a novel synthesis approach using silicon nanopowder and ortho-phosphoric acid at 150 degrees C providing a polycrystalline product. Silicophosphate compounds with sixfold coordinated silicon atoms obtained from pyrophosphoric acid H4P2O7 and tetraalkoxysilanes via a sol-gel route exhibit the same short-range order. The solid products were analyzed with XRD, elemental analysis (ICP-AES), and detailed NMR spectroscopic studies, including H-1, C-13, Si-29, and P-31 MAS-, P-31-Si-29-REDOR, HETCOR, and CP-RFDR experiments. DFT calculations support the structure of Si(HPO4)(2) consisting of layers of [SiO6] octahedra linked by [O3P(OH)] tetrahedra. The OH groups point to the neighboring layers and may be substituted by ethoxy or other groups. KW - Silicon KW - Phosphorus KW - Sol-gel processes KW - NMR spectroscopy KW - Computational chemistry PY - 2019 DO - https://doi.org/10.1002/ejic.201801321 IS - 6 SP - 828 EP - 836 PB - ChemPubSoc AN - OPUS4-48058 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gluth, Gregor A1 - Sturm, Patrick A1 - Greiser, Sebastian A1 - Jäger, Christian A1 - Brouwers, H.J.H. A1 - Kühne, Hans-Carsten T1 - Einkomponentige alkaliaktivierte Bindemittel und Mörtel mit hohem Widerstand gegen Schwefelsäureangriff N2 - Einkomponentige alkaliaktivierte Bindemittel (AAB), d. h. AAB, bei denen der Aktivator als Feststoff im Bindemittel vorliegt, weisen Vorteile hinsichtlich der praktischen Anwendung im Bauwesen gegenüber konventionellen AAB auf. Einkomponentige AAB lassen sich als Gemische aus reaktiver Silica und Natriumaluminat herstellen, wobei die Reaktionsprodukte von der eingesetzten Silica und den Verhältnissen Na2O/Al2O3/SiO2/H2O abhängen: Während Mikrosilica und ähnliche Reststoffe zu zeolithreichen Produkten führen, erhält man aus Reisschalenasche vollständig amorphe Gele (sog. «Geopolymere »). Mörtel auf Basis solcher Bindemittel entsprechen den Anforderungen von DIN 19573:2016-03 hinsichtlich des Widerstands gegen Schwefelsäureangriff (Prüfung bei pH = 1 für 70 d) und sind damit potentiell als Reparatursysteme für Abwasserinfrastruktur geeignet. Untersuchungen mittels 29Si-MAS-NMR und 1H-29Si-Kreuzpolarisations(CP)-MAS-NMR sowie REM-Aufnahmen von erhärteten und dem Schwefelsäureangriff ausgesetzten AAB zeigen, dass der hohe Säurewiderstand v. a. auf die Fällung von Silicagel an der Grenzfläche Mörtel/Säure zurückzuführen ist, wodurch der Korrosionsfortschritt in darunterliegenden Schichten verlangsamt wird. T2 - Tagung Bauchemie der GDCh-Fachgruppe Bauchemie CY - Aachen, Germany DA - 30.09.2019 KW - Alkaliaktivierte Bindemittel KW - Biogene Schwefelsäurekorrosion KW - Abwasserinfrastruktur KW - Reparatursysteme PY - 2019 SP - 107 EP - 113 PB - Gesellschaft Deutscher Chemiker CY - Frankfurt am Main AN - OPUS4-49264 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gluth, Gregor A1 - Sturm, Patrick A1 - Greiser, Sebastian A1 - Jäger, Christian A1 - Kühne, Hans-Carsten ED - Wang, J. ED - Kriven, W. ED - Fey, T. ED - Colombo, P. ED - Weber, W.J. ED - Amoroso, J. ED - Fahrenholtz, W.G. ED - Shimamura, K. ED - Halbig, M. ED - Kirihara, S. ED - Wu, Y. ED - Shurgart, K. T1 - One-part geopolymers and aluminosilicate gel-zeolite composites: factors influencing microstructure and engineering properties N2 - Mixing and curing of geopolymers and related alkali-activated materials without storage and handling of highly alkaline solutions possesses advantages regarding safety and economic viability. One possible approach is to produce these materials from solid silica feedstocks and solid sodium aluminate, and subsequent mixing with water. We present a comparison between geopolymers and aluminosilicate gel-zeolite composites synthesized by this route from different silica feedstocks (by-product silica from chlorosilane production, microsilica, rice husk ash) and with different SiO2/Al2O3 ratios, using results from XRD, NMR, SEM, thermal analysis, mechanical and acid resistance testing. The use of rice husk ash favors formation of a fully amorphous geopolymer with high strength. Utilization of the other silica feedstocks leads to formation of aluminosilicate gel-zeolite composites, the amount and kind of zeolites depending on the feedstock and the SiO2/Al2O3 ratio. These composites show beneficial dehydration behavior, viz. no distinct dehydration step of thermal strain, with the phase assemblage after heating to 1000°C controlled by the starting composition. Mortars produced from both, the geopolymers as well as the composites, exhibit high resistance to sulfuric acid attack, making them promising materials for the construction and the repair of industrial and sewer structures. T2 - 42nd International Conference on Advanced Ceramics and Composites CY - Daytona Beach, FL, USA DA - 21.01.2018 KW - Alkali-activated materials KW - One-part geopolymers KW - Sulfuric acid resistance KW - High-temperature resistance PY - 2019 DO - https://doi.org/10.1002/9781119543381.ch17 VL - 39 IS - 3 SP - 183 EP - 196 PB - John Wiley & Sons AN - OPUS4-47282 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Patrick A1 - Gluth, Gregor A1 - Lindemann, Mathias A1 - Greiser, Sebastian A1 - Jäger, Christian A1 - Brouwers, H.J.H. ED - Bernal, S.A. ED - Provis, J.L. T1 - Structural investigations on one-part geopolymers after different drying regimes T2 - 34th Cement and concrete science conference CY - Sheffield, UK DA - 2015-09-14 KW - Geopolymers KW - One-part mix PY - 2015 SP - 37 EP - 40 AN - OPUS4-34554 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sturm, Patrick A1 - Gluth, Gregor A1 - Jäger, Christian A1 - Brouwers, H.J.H. A1 - Kühne, Hans-Carsten T1 - Sulfuric acid resistance of one-part alkali-activated mortars N2 - One-part alkali-activated (geopolymer) mortars based on three different silica-rich starting materials and sodium aluminate, with and without ground granulated blast furnace slag (GGBFS) addition, were tested regarding sulfuric acid resistance according to DIN 19573:2016-03 (70 days at pH = 1). Corresponding pastes were characterized by XRD, SEM, chemical analysis, 29Si MAS NMR and 1H-29Si CPMAS NMR after water storage and after acid exposure. The mortars exhibited a high resistance against sulfuric acid attack, with the best ones conforming to the requirements of DIN 19573:2016-03. The analytical results showed that this was due to precipitation of silica gel at the acid-mortar interface, which formed a mechanically stable layer that protected the subjacent mortar and thus inhibited further degradation. The addition of GGBFS decreased the acid resistance via formation of expansive calcium sulfate phases. KW - Alkali activated materials KW - Acid resistance KW - Nuclear magnetic resonance KW - One-part geopolymers PY - 2018 DO - https://doi.org/10.1016/j.cemconres.2018.04.009 SN - 0008-8846 VL - 109 SP - 54 EP - 63 PB - Elsevier Ltd. AN - OPUS4-44722 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sturm, Patrick A1 - Gluth, Gregor A1 - Greiser, Sebastian A1 - Jäger, Christian A1 - Brouwers, H.J.H. A1 - Kühne, Hans-Carsten T1 - Investigations on one-part geopolymers synthesized from different silica sources N2 - One-part geopolymers, synthesized from three different silica sources and sodium aluminate, were investigated regarding their microstructure and the evolution of their compressive strength on curing at slightly elevated temperatures. The effect of thermal treatment was studied up to 1000 °C and for the investigation of the chemical durability specific samples were treated with sulfuric acid (H2SO4, pH = 1). Depending on the silica feedstock, different degrees of reaction were observed. One of the silicas had a significantly higher reactivity. For two of the silicas, significant amounts of zeolites occurred as reaction products besides geopolymeric gel, whereas the more reactive silica source lead to the formation of a rather fully condensed geopolymeric network. The composites indicated promising behavior on heating in so far as no distinct shrinkage step occurred in the temperature range of dehydration. Up to 400 °C the residual strength of those mixes increased. Above 800 °C the samples underwent new phase formation. After exposure to sulfuric acid (pH 1; 70 d) specimens showed a residual compressive strength of about 77 % of the reference, indicating high acid resistance. T2 - 6th International Conference on Non-Traditional Cement & Concrete CY - Brno, Czech Republic DA - 19.06.2017 KW - Geopolymers KW - Zeolites KW - Thermal properties KW - Acid resistance KW - Chemical durability PY - 2017 SN - 978-80-214-5507-8 SP - 299 EP - 306 AN - OPUS4-40774 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sturm, Patrick A1 - Greiser, Sebastian A1 - Gluth, Gregor A1 - Jäger, Christian A1 - Brouwers, H.J.H. T1 - Degree of reaction and phase content of silica-based one-part geopolymers investigated using chemical and NMR spectroscopic methods N2 - One-part geopolymers were synthesized from two different silica materials (a silica-rich residue from chlorosilane production and a commercial microsilica) and sodium aluminate at three different SiO2/Al2O3 ratios and a nominal water/solids ratio of 0.5. The degree of reaction of the silica in the cured geopolymers (i.e. the fraction of silica dissolved to form aluminosilicates and minor products) was determined using two different methods: chemical attack with HCl to dissolve the reaction products and evaluation of peak areas of 29Si MAS NMR spectra. It was found that the degree of reaction of the silica decreases with increasing the silica content of the starting mix, and that it is almost constant after 1 day of curing and almost independent from the kind of starting silica. From the results of the NMR-based method, the mean SiO2/Al2O3 ratio of the reaction products (aluminosilicates and minor products) can be estimated to be ca. 2.0, nearly independent of the starting composition of the geopolymers. The dissolution method is biased, but of sufficient precision to be useful for following changes of the degree of reaction. Major crystalline phases in the cured geopolymers are zeolite A and/or hydrosodalite. Depending on the starting composition, the relative amounts of these zeolites vary; additionally, sodalite (only for the residue from chlorosilane production with >1 wt% Cl-), faujasite, and zeolite EMT can appear in the geopolymers. The 29Si and 27Al MAS NMR results indicate mainly Si(4Al) and Al(4Si) sites, in line with the presence of zeolite A, hydrosodalite, sodalite, and geopolymeric gel of comparatively low SiO2/Al2O3 ratio. KW - Geopolymers KW - One-part mix KW - 29Si MAS NMR KW - 27Al MAS NMR KW - Silica KW - Degree of reaction PY - 2015 DO - https://doi.org/10.1007/s10853-015-9232-5 SN - 0022-2461 SN - 1573-4803 VL - 50 IS - 20 SP - 6768 EP - 6778 PB - Springer Science + Business Media B.V. CY - Norwell, Mass. AN - OPUS4-33826 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Greiser, Sebastian A1 - Sturm, Patrick A1 - Gluth, Gregor A1 - Hunger, M. A1 - Jäger, Christian T1 - Differentiation of the solid-state NMR signals of gel, zeolite phases and water species in geopolymer-zeolite composites N2 - Geopolymer-zeolite composites were synthesized using a silica-rich industrial byproduct from chlorosilane production and sodium aluminate. Pastes were cured at 80 °C and 80% RH, and subsequently dried in two different climates: at 23 °C and 50% RH, and under vacuum. 1H MAS, 23Na MAS and 29Si MAS NMR and XRD measurements were performed after the drying procedures as well as after subsequent aging. Zeolite Na-A was found beside traces of faujasite-type zeolite and zeolite EMT as major crystalline phases in the cured composites; the fraction of geopolymeric gel in the reaction products was determined to be ~18% on a molar basis. Various water species could be distinguished using 1H MAS and 1H-29Si CP MAS NMR, applying rotorsynchronized echo experiments. The largest fraction of the pore water resides in the α-cages of the zeolite Na-A and in the geopolymeric gel; in addition, water exists in the β-cages of the zeolites and adsorbed at sodium ions. The water species in α-cages and in the pores of the geopolymeric gel exhibit slightly different chemical shifts of 4.7 ppm and 4.9 ppm, respectively, in the 1H MAS NMR spectra. Changes of the water content in the geopolymer pores of differently dried samples were observed and led to slightly varied chemical shifts in the 29Si MAS NMR spectra too. Measurements after more than 500 days revealed no significant aging effects of the composites, which confirm their chemical stability. KW - Geopolymers KW - Aluminosilicate inorganic polymers KW - Zeolite Na-A KW - Spectroscopy KW - Drying PY - 2017 DO - https://doi.org/10.1016/j.ceramint.2016.11.004 SN - 0272-8842 VL - 43 IS - 2 SP - 2202 EP - 2208 PB - Elsevier AN - OPUS4-38694 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Greiser, Sebastian A1 - Gluth, Gregor A1 - Sturm, Patrick A1 - Brouwers, H.J.H. A1 - Jäger, Christian ED - Bílek, V. ED - Kersner, Z. T1 - 27Al-1H and 27Al-29Si Double resonance NMR of one-part geopolymers N2 - The production and processing of ordinary Portland cement are responsible for nearly 5% of the world C02 emissions. Due to the world’s increasing requirement for building materials, this air pollution is growing up in the next decades. Alternative cement such as geopolymers can reduce these emissions effectively, Conventional geopolymer binders, produced ffom fly ash or metakaolin as aluminosilicate source and water-glass or alkali hydroxide Solutions as activator, are often used and studied. It is known that under appropriate conditions the starting materials form a three-dimensional aluminosilicate structure and create a gel-like matrix, In our case, a silica source from wastewater treatment of chlorosilane production and solid sodium aluminate as starting materials are initiated to harden by water. This procedure is known as “just add water” or “one-part” geopolymer formulation. These composites have significant advantages for use on construction site, but their Chemical structure is not extensively analyzed. In this work, a well known one-part geopolymer is investigated by 'H and 27A1 magic-angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy. Furthermore, it is shown that overlapping NMR lines can resolved with echo experiments and T2 - NTCC2014 - International conference on non-traditional cement and concrete CY - Brno, Czech Republic DA - 16.06.2014 KW - Geopolymers KW - One-part formulation KW - Zeolite Na-A KW - NMR KW - REDOR PY - 2014 SN - 978-80-214-4867-4 SP - 91 EP - 94 PB - Novpress AN - OPUS4-31224 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Greiser, Sebastian A1 - Gluth, Gregor A1 - Sturm, Patrick A1 - Jäger, Christian T1 - Correction: 29Si{27Al}, 27Al{29Si} and 27Al{1H} double-resonance NMR spectroscopy study of cementitious sodium aluminosilicate gels (geopolymers) and gel–zeolite composites N2 - Correction for ‘29Si{27Al}, 27Al{29Si} and 27Al{1H} double-resonance NMR spectroscopy study of cementitious sodium aluminosilicate gels (geopolymers) and gel–zeolite composites’ by Sebastian Greiser et al., RSC Adv., 2018, 8, 40164–40171, https://doi.org/10.1039/C8RA09246J. PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635365 DO - https://doi.org/10.1039/d3ra90078a SN - 2046-2069 VL - 13 IS - 37 SP - 26148 PB - Royal Society of Chemistry (RSC) CY - London AN - OPUS4-63536 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hemmann, Felix A1 - Agirrezabal-Telleria, Iker A1 - Jäger, Christian A1 - Kemnitz, E. T1 - Quantification of acidic sites of nanoscopic hydroxylated magnesium fluorides by FTIR and 15N MAS NMR spectroscopy N2 - Lewis and Brønsted sites were quantified in a series of weak acidic hydroxylated magnesium fluorides by Fourier transform infrared spectroscopy (FTIR) and solid state nuclear magnetic resonance spectroscopy (NMR) with pyridine as probe molecule. Molar extinction coefficients, which are necessary for quantitative FTIR measurements, were calculated by an easy approach. It utilizes the fact that both signals, used for the quantification by FTIR, are caused by the same deformation vibration mode of pyridine. Comparison of quantitative FTIR experiments and quantification by NMR shows that concentrations of acidic sites determined by FTIR spectroscopy have to be interpreted with caution. Furthermore, it is shown that the transfer of molar extinction coefficients from one catalyst to another may lead to wrong results. Molar extinction coefficients and concentrations of acidic sites determined by FTIR spectroscopy are affected by grinding and probably the particle size of the sample. High temperature during FTIR experiments has further impact on the quantification results. KW - Acidity KW - Fluoride catalyst KW - Infrared spectroscopy KW - Adsorption of pyridine KW - Molar extinction coefficient determination PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-351448 DO - https://doi.org/10.1039/C5RA15116C SN - 2046-2069 VL - 5 IS - 109 SP - 89659 EP - 89668 PB - RSC Publishing CY - London AN - OPUS4-35144 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hemmann, Felix A1 - Jäger, Christian A1 - Kemnitz, E. T1 - Comparison of acidic site quantification methods for a series of nanoscopic aluminium hydroxide fluorides N2 - Quantitative determination of acidic surface sites is highly important for the characterization of solid acids because the activity of a catalyst is often related to the concentration of these sites. A recently developed method using 15N Nuclear Magnetic Resonance spectroscopy (NMR) for the quantification of acidic Lewis and Brønsted sites has been tested for a series of nanoscopic aluminum hydroxide fluorides. Comparison with other methods for the quantitative determination of acidic sites shows that this 15N NMR quantification method is a promising technique for the comprehensive investigation of acidic sites. Three different acidic sites, one Brønsted and two Lewis sites, can be distinguished by their 15N chemical shifts of pyridine and simultaneously quantified under conditions corresponding to catalytic reaction conditions. Determination of the individual concentrations of acidic sites allows further insight into the catalytic process. It was found that the concentration of Brønsted sites correlates with catalyzed conversion of citronellal to isopulegol in the investigated series of catalysts. Additionally, investigations indicate that one of the Lewis sites become blocked during the reaction of citronellal. KW - Solid acids KW - TOF KW - NH3-TPD KW - Progressive catalyst poisoning KW - FTIR KW - Quantitative NMR KW - Solid state NMR PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-323280 DO - https://doi.org/10.1039/c4ra09477h SN - 2046-2069 VL - 4 IS - 100 SP - 56900 EP - 56909 PB - RSC Publishing CY - London AN - OPUS4-32328 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Greiser, Sebastian A1 - Gluth, Gregor A1 - Sturm, Patrick A1 - Jäger, Christian T1 - 29Si{27Al}, 27Al{29Si} and 27Al{1H} double-resonance NMR spectroscopy study of cementitious sodium aluminosilicate gels (geopolymers) and gel-zeolite composites N2 - The influence of starting materials and synthesis route on the properties and the structure of cementitious sodium aluminosilicate gels is not fully understood, partly due their amorphous nature and the fact that they often contain residual reactants, which can make the results of single-pulse NMR spectroscopy applied to these materials difficult to interpret or ambiguous. To overcome some of these limitations, 29Si{27Al} TRAPDOR NMR as well as 27Al{29Si} and 27Al{1H} REDOR NMR spectroscopy were applied to materials synthesized by the one-part alkali-activation route from three different amorphous silica starting materials, including rice husk ash. The latter led to formation of a fully amorphous sodium aluminosilicate gel (geopolymer), while the materials produced from the other silicas contained amorphous phase and crystalline zeolites. Application of the double-resonance NMR methods allowed to identify hydrous alumina gel domains in the rice husk ash-based material as well as significantly differing amounts of residual silica in the three cured materials. Four-coordinated Al existed not only in the aluminosilicate gel framework but also in a water-rich chemical environment with only a small amount of Si in proximity, likely in the alumina gel or possibly present as extra-framework Al in the aluminosilicate gel. The results demonstrate how the employment of different silica starting materials determines the phase assemblage of one-part alkali-activated materials, which in turn influences their engineering properties such as the resistance against chemically/biologically aggressive media. KW - Alkali-activated materials KW - Solid-state NMR KW - Aluminium hydroxide KW - Rice husk ash PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-469353 DO - https://doi.org/10.1039/C8RA09246J SN - 2046-2069 VL - 8 IS - 70 SP - 40164 EP - 40171 PB - Royal Society of Chemistry (RSC) CY - London AN - OPUS4-46935 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kervarec, M.-C. A1 - Kemnitz, E. A1 - Scholz, G. A1 - Rudic, S. A1 - Jäger, Christian A1 - Braun, T. A1 - Michalchuk, Adam A1 - Emmerling, Franziska T1 - A HF Loaded Lewis-Acidic Aluminium Chlorofluoride for Hydrofluorination Reactions N2 - The very strong Lewis acid aluminium chlorofluo-ride (ACF) was loaded with anhydrous HF. The interactionbetween the surface of the catalyst and HF was investigatedusing a variety of characterization methods, which revealed he formation of polyfluorides. Moreover, the reactivity ofthe HF-loaded ACF towards the hydrofluorination of alkyneswas studied. KW - Aluminium KW - HF KW - Hydrofluorination KW - Metal fluorides PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508360 DO - https://doi.org/10.1002/chem.202001627 VL - 26 SP - 1 PB - Wiley Online Libary AN - OPUS4-50836 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fischer, Franziska A1 - Greiser, Sebastian A1 - Peifer, Dietmar A1 - Jäger, Christian A1 - Rademann, K. A1 - Emmerling, Franziska T1 - Mechanochemically Induced Conversion of Crystalline Benzamide Polymorphs by Seeding N2 - Benzamide has been known for its polymorphism for almost 200 years.Three polymorphic forms are described. To date,itwas only possible to crystallizeametastable form in amixture together with the thermodynamically most stable form I. Acomplete transformation of form Iinto the metastable form III by mechanochemical treatment has been achieved. Catalytic amounts of nicotinamide seeds were used to activate the conversion by mechanochemical seeding. NMR experiments indicated that the nicotinamide molecules were incorporated statistically in the crystal lattice of benzamide form III during the conversion. The transformation pathway was evaluated using in situ powder X-ray diffraction. KW - Nicotinamide KW - Benzamide KW - In situ reactions KW - Mechanochemistry KW - Polymorphs PY - 2016 DO - https://doi.org/10.1002/anie.201607358 VL - 128 IS - 46 SP - 14493 EP - 14497 PB - WILEY-VCH CY - Weinheim AN - OPUS4-38472 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wawrzyn, Eliza A1 - Schartel, Bernhard A1 - Seefeldt, Henrik A1 - Karrasch, Andrea A1 - Jäger, Christian T1 - What reacts with what in bisphenol A polycarbonate/silicon rubber/bisphenol A bis(diphenyl phosphate) during pyrolysis and fire behavior? N2 - The pyrolysis and flame retardancy of a bisphenol A polycarbonate/silicon rubber/bisphenol A bis(diphenyl phosphate) (PC/SiR/BDP) blend were investigated and compared to those of PC/BDP and PC/SiR. The impact modifier SiR consists mainly of poly(dimethylsiloxane) (PDMS > 80 wt %). The pyrolysis of PC/SiR/BDP was studied by thermogravimetry (TG), TG–FTIR to analyze the evolved gases, and a Linkam hot stage cell within FTIR as well as 29Si NMR and 31P NMR to analyze the solid residue. The fire performance was determined by PCFC, LOI, UL 94, and a cone calorimeter under different external irradiations. The fire residues were studied by using ATR-FTIR as well as the additional binary systems PC + PDMS, PC + BDP, and BDP + PDMS, focusing on the specific chemical interactions. The decomposition pathways are revealed, focusing on the competing interaction between the components. Fire retardancy in PC/SiR/BDP is caused by both flame inhibition in the gas phase and inorganic-carbonaceous residue formation in the condensed phase. The PC/SiR/BDP does not work as well superimposing the PC/SiR and PC/BDP performances. PDMS reacts with PC and BDP, decreasing BDP's mode of action. Nevertheless, the flammability (LOI > 37%, UL 94 V-0) of PC/SiR/BDP equals the high level of PC/BDP. Indeed, SiR in PC/SiR/BDP is underlined as a promising impact modifier in flame-retarded PC/impact modifier blends as an alternative to highly flammable impact modifiers such as acrylonitrile–butadiene–styrene (ABS), taking into account that the chosen SiR leads to PC blends with a similar mechanical performance. KW - PC KW - BDP KW - PDMS KW - Flame retardancy KW - Flammability KW - Decomposition KW - Pyrolysis PY - 2012 DO - https://doi.org/10.1021/ie201908s SN - 0888-5885 SN - 1520-5045 VL - 51 IS - 3 SP - 1244 EP - 1255 PB - American Chemical Society CY - Washington, DC AN - OPUS4-25460 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wawrzyn, Eliza A1 - Schartel, Bernhard A1 - Karrasch, Andrea A1 - Jäger, Christian T1 - Flame-retarded bisphenol A polycarbonate/silicon rubber/bisphenol A bis(diphenyl phosphate): Adding inorganic additives N2 - Various inorganic additives belonging to four different groups: layered materials, metal hydroxides, metal oxides/carbonate and metal borates are investigated in bisphenol A polycarbonate/silicon rubber/bisphenol A bis(diphenyl phosphate) (PC/SiR/BDP) to improve flame retardancy. The pyrolysis, reaction to small flame and fire behaviour of the blends are characterised and structure–property relationships discussed. Among the added layered materials, talc functions as an inert filler with potential for commercialisation, whereas organically modified montmorillonite (LS) enhances decomposition. PC/SiR/BDP + talc and PC/SiR/BDP + LS reinforce the char and induce a flow limit. The different dispersion and location of boehmite (AlO(OH)) nano-particles and Mg(OH)2 micro-particles determine the impact on performance. PC/SiR/BDP + Mg(OH)2 shows additional hydrolysis and thus reduced flame retardancy. AlO(OH) is embedded in SiR and thus behaves as an inert filler. Both additives worked as smoke suppressants. Using selective filling with nano-particles is proposed as an interesting route for flame retardancy in PC/SiR blends. Adding metal oxides and carbonate (MgO, CaCO3 and SiO2) changes the decomposition pathways of PC/SiR/BDP, worsening the fire performance of PC/SiR/BDP. CaCO3 harbours the potential to intumescence, even though an early collapse of the char structure occurred. Adding hydrated metal borates, CaB, MgB and ZnB, changes the pyrolysis and flame retardancy action. Smoke suppression occurs; LOI is improved as well as UL 94 classification. ZnB performs better than MgB and CaB. The comprehensive study, also based on systematic material variation, delivers valuable guidelines for future development of flame-retarded multi-component PC blends. KW - Flame retardancy KW - Polycarbonate blends KW - Aryl phosphate KW - Inorganic fillers PY - 2014 DO - https://doi.org/10.1016/j.polymdegradstab.2013.08.006 SN - 0141-3910 SN - 1873-2321 VL - 106 SP - 74 EP - 87 PB - Applied Science Publ. CY - London AN - OPUS4-30952 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karrasch, Andrea A1 - Wawrzyn, Eliza A1 - Schartel, Bernhard A1 - Jäger, Christian T1 - Solid-state NMR on thermal and fire residues of bisphenol A polycarbonate/silicone acrylate rubber/bisphenol A bis(diphenyl-phosphate)/(PC(SiR/BDP) and PC/SiR/BDP/zinc borate (PC/SiR/BDP/ZnB) - Part 1: PC charring and the impact of BDP and ZnB N2 - Structural changes in the condensed phase of bisphenol A polycarbonate (containing 0.45 wt% poly (tetrafluoroethylene))/silicone acrylate rubber/bisphenol A bis(diphenyl-phosphate) (PC/SiR/BDP) and PC/SiR/BDP/zinc borate (PC/SiR/BDP/ZnB) during thermal treatment in nitrogen atmosphere and in fire residues were investigated by solid-state NMR. H-1, B-11, C-13 and P-31 NMR experiments using direct excitation with a single pulse and H-1-P-31 cross-polarization (CP) were carried out including 31P(1 H) and C-13{P-31}double-resonance techniques (REDOR: Rotational Echo Double Resonance) on a series of heat-treated samples (580 K-850 K). Because many amorphous phases occur in the solid residues, and solid-state NMR spectroscopy addresses the most important sites carbon, phosphorus and boron, this paper is the key analytical approach for understanding the pyrolysis and flame retarding phenomenon in the condensed phase of PC/SiR/BDP and PC/SiR/BDP/ZnB. For the system PC/SiR/BDP it is shown that (i) at temperatures around 750-770 K (main decomposition step) carbonaceous charring of PC occurs and arylphosphate structures are still present, reacted in part with the decomposing PC; (ii) for higher temperatures from 770 K the phosphorus remaining in the solid phase increasingly converts to amorphous phosphonates and inorganic orthophosphates with a minor amount of crystalline orthophosphates; and (iii) H-1-P-31{H-1} CP REDOR and H-1-C-13{P-31} CP REDOR NMR experiments suggest that the phosphates and phosphonates are bound via oxygen to aromatic carbons, indicating the interaction with the carbonaceous char. When ZnB is added to the system PC/SiR/BDP, (i) ZnB leads to a slightly enhanced PC decomposition for temperatures below 750 K; (ii) alpha-Zn-3(PO4)(2) and borophosphate (BPO4) are formed in small amounts at high temperatures suggesting a reaction between BDP and ZnB during thermal decomposition; and (iii) most of the borate remains in the solid residues, forming an amorphous pure borate network, with the BO3/BO4 ratio increasing with higher temperatures. The NMR data of thermal and fire residues are highly correlated, underlining the importance of this work for understanding the pyrolysis and flame retardancy mechanisms in the condensed phase during the burning of the PC/SiR blends. (C) 2010 Elsevier Ltd. All rights reserved. KW - Flame retardance KW - NMR KW - Polycarbonate (PC) blends KW - Bisphenol-A bis(diphenyl)phosphate (BDP) KW - Zinc borate PY - 2010 DO - https://doi.org/10.1016/j.polymdegradstab.2010.07.034 SN - 0141-3910 SN - 1873-2321 VL - 95 IS - 12 SP - 2525 EP - 2533 PB - Applied Science Publ. CY - London AN - OPUS4-22647 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karrasch, Andrea A1 - Wawrzyn, Eliza A1 - Schartel, Bernhard A1 - Jäger, Christian T1 - Solid-state NMR on thermal and fire residues of bisphenol A polycarbonate/silicone acrylate rubber/bisphenol A bis(diphenyl-phosphate)/(PC(SiR/BDP) and PC/SiR/BDP/zinc borate (PC/SiR/BDP/ZnB) - Part II: The influence of SiR N2 - Solid residues of bisphenol A polycarbonate (containing 0.45 wt% poly(tetrafluoroethylene))/silicone acrylate rubber/bisphenol A bis(diphenyl-phosphate) (PC/SiR/BDP) and PC/SiR/BDP/zinc borate (PC/SiR/BDP/ZnB) after thermal treatment were investigated by solid-state and liquid-state NMR, focusing on the role and interaction of SiR with the other components of the polymer blend. In PC/SiR/BDP, part of the SiR reacts to an amorphous silicate network rather than being completely released in the gas phase. The silicate network consists of Q4 and Q3 groups formed via intermediate D and T groups. The D groups are formed by a reaction of SiR with bisphenol-A units as well as phenyl groups of PC and BDP. In addition a small amount of silicon diphosphate was observed after thermal treatment at temperatures higher than 810 K. The same decomposition products (without SiP2O7) occur in the solid residues of PC/SiR/BDP/ZnB samples. The formation of intermediate D and T groups occurs earlier, at slightly lower temperatures. Any formation of a borosilicate network was excluded. The results also apply for the fire residues of PC/SiR/BDP and PC/SiR/BDP/ZnB and are thus valuable for understanding the impact of SiR on pyrolysis and flame retardancy mechanisms in the condensed phase during the burning of PC/SiR/BDP blends. SiR was found to influence the pyrolysis and the char formed. Beyond the replacement of highly combustible mechanical modifiers, SiR harbours the potential to enhance flame retardancy. KW - Flame retardance KW - 29Si NMR KW - Polycarbonate (PC) blends KW - Bisphenol A bis(diphenyl)phosphate (BDP) KW - Silicone rubber PY - 2010 DO - https://doi.org/10.1016/j.polymdegradstab.2010.07.030 SN - 0141-3910 SN - 1873-2321 VL - 95 IS - 12 SP - 2534 EP - 2540 PB - Applied Science Publ. CY - London AN - OPUS4-22648 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Karrasch, Andrea A1 - Jäger, Christian T1 - Thermal decomposition behaviour of flame-retarded Bisphenol-a Polycarbonate: a solid-state NMR investigation T2 - Polydays 2008, Freie Universität Berlin CY - Berlin, Germany DA - 2008-10-01 PY - 2008 N1 - Geburtsname von Wawrzyn, Eliza: Pikacz, E. - Birth name of Wawrzyn, Eliza: Pikacz, E. AN - OPUS4-17960 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Díez, I. A1 - Emmerling, Franziska A1 - Malz, Frank A1 - Jäger, Christian A1 - Schulz, B. A1 - Orgzall, I. T1 - Origin of templating processes in polypyrrole synthesis N2 - The supermolecular mechanism of the template-mediated oxidative polymerization of pyrrole is investigated in detail. It is shown for the first time that 2,5-bis(pyrrol-2-yl)pyrrolidyl complexes with aromatic sulfonic acids such as %#946;-naphtalenesulfonic acid or para-toluenesulfonic acid are formed in the early polymerization step. The crystalline acid–base complexes are isolated and their crystal structures are analyzed. A 2,5-bis(pyrrol-2-yl)pyrrolidyl cation is common to both complexes and forms an inner salt with the sulfonic acid anion. As concluded from NMR investigations the synthesis using sulfonic acids results in a high stereo selectivity with respect to the trans conformation of the pyrrolidyl ring compared with the classical synthesis routine of this compound using hydrochloric acid. The needle-like crystals of the complexes act as hard templates during the next step of the polymerization and result in tubular morphologies of the polypyrrole. KW - Polypyrrole KW - Pyrrole complex PY - 2008 DO - https://doi.org/10.1016/j.matchemphys.2008.05.057 SN - 0254-0584 VL - 112 IS - 1 SP - 154 EP - 161 PB - Elsevier CY - Amsterdam AN - OPUS4-17859 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -