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 - 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 - 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 - CONF A1 - Karrasch, Andrea A1 - Jäger, Christian A1 - Rosenau, T. 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 - 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 - CONF A1 - Karrasch, Andrea A1 - Jäger, Christian A1 - Braun, Ulrike A1 - Schartel, Bernhard 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 - Karrasch, Andrea A1 - Braun, Ulrike A1 - Schartel, Bernhard A1 - Jäger, Christian T1 - Festkörper-NMR Untersuchungen an flammgeschützten Polymeren T2 - Seminar "Festkörper-NMR-Methoden und Anwendungen in der Materialforschung", Universität Tübingen CY - Bad Hindelang, Germany DA - 2008-07-13 PY - 2008 AN - OPUS4-17899 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Karrasch, Andrea A1 - Jäger, Christian A1 - Wawrzyn, Eliza A1 - Schartel, Bernhard 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 - CONF A1 - Karrasch, Andrea A1 - Jäger, Christian A1 - Wawrzyn, Eliza A1 - Schartel, Bernhard T1 - Thermal decomposition of PDMS in flame-retarded Bisphenol-a Polycarbonate: a solid-state NMR investigation T2 - FRPM 09 12th European Conference on Fire Retardant Polymers CY - Poznan, Poland DA - 2009-08-31 PY - 2009 AN - OPUS4-19998 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Karrasch, Andrea A1 - Jäger, Christian A1 - Wawrzyn, Eliza A1 - Schartel, Bernhard T1 - Thermal decomposition of PDMS in flame-retarded Bisphenol-a Polycarbonate: a solid-state NMR investigation T2 - GDCh Tagung Magnetische Resonanz 2009 CY - Dresden, Germany DA - 2009-09-21 PY - 2009 AN - OPUS4-20005 LA - deu 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 - 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 - 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 -