TY - CONF A1 - Geburtig, Anja A1 - Wachtendorf, Volker A1 - Falkenhagen, Jana T1 - Combined impact of UV radiation and nitric acid (HNO3) on HDPE jerrycans – comparison of outdoor and lab test N2 - A damaging action of HNO3-55% only occurs in combination with its decomposition into nitrous gases, which can be caused by UV radiation. In a laboratory test, transparent HDPE jerrycans have been exposed to both UV radiation and 55 wt-% nitric acid solution at (41 ± 2)°C, for up to 20 days. For comparison, UV radiant exposure (21 days) and nitric acid exposure (up to 6 weeks) were performed separately, at nearly equal temperatures. The respective damages are compared with FTIR spectroscopy in ATR and HT-gel permeation chromatography (GPC) on a molecular level and with hydraulic internal pressure testing as a component test. For the used jerrycans, relevant oxidation can only be found after the combined exposure. The gradual increase in oxidative damage shows the good reproducibility of the lab exposure. The decomposition of nitric acid into nitrous gases by UV radiation – as well as the jerrycan oxidation – is also observed at lower HNO3 concentration (28 wt- %). Similar results are obtained after outdoor tests. Again, the damage occurs only after combined exposure, in contrast to the exposures to UV only and to HNO3 only, which were conducted in parallel. Outdoor exposures are most readily accepted as they represent possible end-use conditions. However, the reproducibility of these exposures is poor due to the large temporal variations in weather. There are also several safety risks, which is why the number of replicates remains limited. Since the outdoor and lab exposure tests show the same qualitative results, it is appropriate to conduct systematic studies in the laboratory. After 6 days of lab exposure, the oxidation damage is rated as critical, which corresponds to about 1/10 year in Central Europe, according to the UV radiant exposure. It should be noted that this amount can also occur in two sunny weeks. T2 - 24th iapri World Packaging Conference CY - Valencia, Spain DA - 17.06.2024 KW - Ppolyethylene KW - UV exposure KW - Nitric acid KW - Oxidation PY - 2024 VL - 2 SP - 30 EP - 37 PB - ITENE AN - OPUS4-60414 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Coupling of chromatographic and spectrometric techniques for polymer characterization N2 - Coupling of chromatographic and spectrometric techniques for polymer characterization; focus topics: LCxMALDI-TOF-MS and UPLC x ESI-TOF-MS T2 - 16. Tagung des Arbeitskreises Polymeranalytik CY - Online meeting DA - 22.03.2022 KW - Liquid chromatography KW - Mass spectrometry KW - Polymers KW - Two-dimensional chromatography (2D-LC) PY - 2022 AN - OPUS4-54567 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen T1 - Polymer mass spectrometry at BAM with special emphasis on MALDI and ESI N2 - Since its introduction mass spectrometric techniques like Matrix-assisted Laser Desorption/ionization (MALDI) and Electrospray Ionization (ESI) have become indispensable for synthetic polymer analyses. Ideally, various polymer properties (monomer structure, masses, mass distribution, end groups) can be determined simultaneously. However, in real life these experiments are always affected by important structural parameters and instrumental limitations. A short introduction focussing on latest findings with respect to ionisation principles and mechanisms will be given. Recent results from our group will be presented and efforts to avoid common drawbacks of polymer mass spectrometry will be discussed. In this regard, MALDI - Imaging mass spectrometry and the 2D hyphenation of MS with different chromatographic separation techniques were especially useful, since they can provide additional information and reduce the complexity of polymer analyses. T2 - 21. European Symposium on Polymer Spectroscopy CY - Linz, Austria DA - 13.01.2020 KW - Mass spectrometry KW - MALDI-TOF MS KW - ESI-TOF MS KW - Polymer PY - 2020 AN - OPUS4-50260 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - You, Zengchao T1 - Separation of polysterene nanoparticles with different coatings using 2D off-line coupling of asymmetrical flow field flow fractionation and capillary electrophoresis N2 - The successful off-line coupling of asymmetrical flow field flow fractionation (AF4) and capillary electrophoresis (CE) for Separation of nanoparticles (NPs) with different surface coatings was shown. Two mixtures of polystyrene nanoparticles (PS-NPs) with comparable core sizes (20 nm and 50 nm) but different coatings (no coating/carboxyl-coated) were studied. Separation in either method resulted in non-baseline resolved or non-separated peaks. In contrast, two-dimensional off-line coupling of AF4 and CE resulted in clearly separated regions in their 2 D plots and can obviouly improve separation resolution. T2 - FFF 2020 CY - Wien, Austria DA - 23.02.2020 KW - Capillary electrophoresis KW - Nanoparticle PY - 2020 AN - OPUS4-50487 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - 70 years size exclusion chromatography - An ongoing challenge N2 - The reason for our current activities is that polymers may also be subject to REACh regulations in the future. In this context, the determination of oligomer content is important. SEC is still the method of choice for determining molar mass distribution. The regulations aim for narrow limits and SEC has rather large error margins, which are well known to all experts. Different polymers need different methods. What to do when samples with a wide range of practical aspects, samples with higher distribution range, reduced solubility, including side components, gel content etc. need be analyzed? A concept for round robin tests and first impressions will be presented. T2 - Analytical Solutions 2025 CY - Ede, Netherlands DA - 04.06.2025 KW - Polymers KW - Size exclusion chromatography KW - REACH KW - Round Robin Tests PY - 2025 AN - OPUS4-63310 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fink, Friedrich T1 - Mechanochemical valorisation of kraft-lignin N2 - As one of nature's largest carbon sources with an annual production of around 20 billion tonnes, lignin is the third most abundant biopolymer on the planet. It becomes available as technical lignin, which is produced as a by-product in the pulp and paper industry and in smaller quantities in second generation biofuel refineries. Current estimates suggest that less than 10% of all technical lignin is reused. The high polydispersity, complex heterogeneous structure and uncertain reactivity are the major limiting factors for further processing. The most common applications for various technical lignins without extensive modifications are for example: Surface active substances, additives in bitumen, cement and animal feed. One way to make lignin usable is to break the structure into oligomer units and thus reduce the polydispersity and average molar mass. In addition, it is advantageous to introduce new functionalities such as hydroxyl or carbonyl groups when splitting the high-molecular-weight (HMW) fractions, or to convert existing functionalities. In this study, a mechanochemical method is presented that can degrade and modify technical kraft lignin by means of sodium percarbonate (SPC). T2 - 10th Intern. Symp. on the Separation and Characterisation of Natural and Synthetic Macromolecules (SCM-10) CY - Amsterdam, Netherlands DA - 01.02.2023 KW - Technical Lignin KW - Mechanochemical oxidation PY - 2023 AN - OPUS4-57001 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana T1 - Challenges of sec and the necessity of round robin tests N2 - Size exclusion chromatography (SEC) is still the method of choice for determining the molar mass and molar mass distribution of macromolecules. From the distribution curve molar mass averages and the oligomer content (percentage of peak area smaller than 1000 g/mol and 500 g/mol) of polymers can be derived. The determination of oligomer content is important, because it is often used in regulatory contexts as a measure of small, mobile and potentially more toxic parts of the polymer. Polymer regulations are of increasing political and societal importance. Regulations often strive for narrow limits. But SEC has rather large error margins of 10-20% for the molar mass determination performed in different laboratories or on different instruments. These variances are well known to all experts and users and have been investigated in several round robin tests in the past. These resulted in DIN and ISO standards which, in our opinion, no longer meet today's requirements. Gaps have been identified that require further harmonization. Different polymer types or classes require different methods. On the other hand, as far as we know, the margins of error in determining oligomer content have not yet been investigated. It is expected that the variation will be rather high. This is because it depends on many factors related to the experimental conditions (column sets used, solvent, temperatures, sample preparation) on the one hand, and the data evaluation mechanisms (choice of baseline and peak limits) on the other. In order to actually measure the error margins and to support this with actual data a round robin test has been performed from June to November 2024 with approx. 40 participating laboratories. Three different solvents were selected, namely THF, DMAc or DMF and water. The samples were selected taking into account a wide range of practical aspects far from narrowly distributed standards: e.g higher distribution range, reduced solubility, included side components, copolymers and dispersions with gel content. In this contribution we will present the detailed concept of this round robin test and impressions T2 - 2025 Polymer Separations GNT meeting, Dow CY - Online meeting DA - 25.02.2025 KW - Polymers KW - Size exclusion chromatography KW - REACH PY - 2025 AN - OPUS4-63314 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Falkenhagen, Jana A1 - Fink, Friedrich T1 - Biobased and biodegradable polymers - sustainability and circular economy N2 - The presentation shows recent results on the synthesis and modification of environmentally relevant polymers based on renewable resources and the associated development of robust, high quality analytical methods. The first topic presents analytical results for star-shaped polylactides with different degrees of functionalisation. It is shown how liquid chromatography and mass spectrometry methods complement each other in a proven way to obtain accurate molar masses and to quantify chemically heterogeneous species. The second part presents an approach to incorporate lignin into epoxy matrices to obtain covalently adaptable epoxy networks that can be reprocessed and reused. T2 - 11th International Symposium on the Separation and Characterization of Natural and Synthetic Macromolecules CY - Amsterdam, Netherlands DA - 21.01.2025 KW - Polylactides KW - Ligninbased thermosets KW - MALDI-TOF-MS KW - Gradient elution liquid adsorption chromatography KW - Atomic force spectroscopy KW - FT-IR PY - 2025 AN - OPUS4-62532 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Abderrazak, H. T1 - Synthesis of new bio based adsorbent phases N2 - Over the years, industrial and human activities and agricultural practices have caused a serious threat to human health and the environment. Indeed, it has been demonstrated that these activities are responsible for the presence of pollutants in the soil, air and water. Water is one of the most strategic issues today, as it is associated with the living world. Therefore, water pollution is becoming a universal scourge that leads to environmental degradation, decrease of water quality and threatens public health. Water pollution is mainly due to the discharge of certain harmful chemical compounds that are not very or not at all biodegradable (phenolic compounds, heavy metals, hydrocarbons, dyes, pesticides, etc.) by various industries: chemical, pharmaceutical, textile, food processing, etc. The impact of these industrial effluents on fauna and flora is very harmful. A sensitization of the socio-economic actors and the public, accompanied by a severe regulation in relation to the discharges, would contribute to fight against this drift, but also, by the development of effective methods allowing to remove these pollutants, not only in an analytical purpose but also of depollution. Thus and within the framework of the preservation of an environment with regard to any anthropogenic activity, our research topic relates to the use of original biosourced polymeric phases for the extraction of the organic compounds and the heavy metals in aqueous mediums. Therefore, we have proceeded to the synthesis and characterization of a large variety of monomers, polymers and cross-linked materials. These products, partially derived from biomass, contain various functional groups with the ability to interact with chemical components without discriminating effect. The developed polymer phases have been successfully used for the adsorption of some organic pollutants and heavy metals in synthetic aqueous solutions. T2 - 12. Journees maghreb-europe. Matériaux et Applications aux Dispositifs et Capteurs CY - Monastir, Tunisia DA - 08.11.2022 KW - Organic-inorganic adsorbents KW - Semi-Interpenetrating Network KW - Poly(ether-sulfone) KW - Reversible adsorption. PY - 2022 AN - OPUS4-56286 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weidner, Steffen T1 - MALDI TOF MS zur Aufklärung von Kristallisationsprozessen in Polyestern N2 - MALDI TOF Massenspektrometrie wurde verwendet, um Kristallisationsprozesse in Polyestern (Polylactide, Polyglycolide) zu untersuchen. Dabei konnte gezeigt werden, dass Zyklen und Linearen simultan, aber in unterschiedlichen Kristalliten, kristallisieren. Die dabei ablaufenden Umesterungen (Transesterifizierungen) konnten mit der MALDI TOF Massenspektrometrie nachgewiesen werden. Damit wurde ein völlig neues Anwendungsgebiet dieser MS Methode demonstriert. T2 - 28. Kolloquium Massenspektrometrie von Polymeren CY - Berlin, Germany DA - 14.05.2024 KW - MALDI TOF MS KW - Bioabbaubare Polymere KW - Crystallinity PY - 2024 AN - OPUS4-60029 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jlalia, I. A1 - Chabbah, T. A1 - Chatti, S. A1 - Schiets, F. A1 - Casabianca, H. A1 - Marestin, C. A1 - Mercier, R. A1 - Weidner, Steffen A1 - Kricheldorf, H. R. A1 - Errachid, A. A1 - Vulliet, E. A1 - Hammani, M. A1 - Jaffrezic-Renault, N. T1 - Alternating bio-based pyridinic copolymers modified with hydrophilic and hydrophobic spacers as sorbents of aromatic pollutants N2 - The main objective of this work was to design new advanced sorbent phases, alternating copolymers, derived from isosorbide and 2,6-difluorpyridine, to be used for the removal of aromatic organic pollutants present in water at low concentrations. Six different monomers, dianhydrohexitols isomers and bisphenol derivatives, weresynthesized in order to make it possible to study their hydrophilic and hydrophobiceffect on the sorption efficiency of the resulting polymeric phases. Before this study, we have confirmed the chemicals structures, molecular weights, and thermal properties of the obtained polymeric phases. Sorption results show a higher adsorption efficiency of P6 co-poly(ether-pyridine) based on bisphenol substituted with pyridineunits, for all tested pollutants, hydrophobic and hydrophilic ones, due to its less compact structure. Two aromatic organic pollutants, p-hydroxybenzoic acid and toluicacid, were selected as sorbates to study the adsorption characteristic, kinetics and isotherms of the copoly(ether pyridine) P6. Langmuir model led to a better fitting of the sorption isotherms; the sorption of toluic acid is easier than of that p-hydroxybenzoic acid. Comparing 1/n values for benzoic acid was two time lower for P6 compared to that for biochar and for crosslinked methacrylate resin, showing a higher efficiency KW - Alternating co-poly(ether pyridine)s KW - Aromatic organic compounds, KW - Biosourced isosorbide KW - Sorption isotherm KW - Sorption mechanism PY - 2021 DO - https://doi.org/10.1002/pat.5578 VL - 33 IS - 4 SP - 1057 EP - 1068 PB - Wiley Online Library AN - OPUS4-54031 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fink, Friedrich A1 - Stawski, Tomasz M. A1 - Stockmann, Jörg Manfred A1 - Emmerling, Franziska A1 - Falkenhagen, Jana T1 - Surface Modification of Kraft Lignin by Mechanochemical Processing with Sodium Percarbonate N2 - In this article, we present a novel one-pot mechanochemical reaction for the surface activation of lignin. The process involves environmentally friendly oxidation with hydrogen peroxide, depolymerization of fractions with high molecular mass, and introduction of new carbonyl functions into the lignin backbone. Kraft lignin was ground with sodium percarbonate and sodium hydroxide in a ball mill at different time intervals. Analyses by infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR), size exclusion chromatography (SEC), dynamic vapor sorption (DVS), and small-angle X-ray scattering (SAXS) showed significant improvements. After only 5 min of reaction, there was a 47% reduction in mass-average molecular weight and an increase in carboxyl functionalities. Chemical activation resulted in an approximately 2.8-fold increase in water adsorption. Principal component analysis (PCA) provided further insight into the correlations between IR spectra and SAXS parameters KW - Kraft Lignin KW - Mechanochemical oxidation KW - SEC KW - FTIR KW - SAXS KW - PCA PY - 2023 DO - https://doi.org/10.1021/acs.biomac.3c00584 SN - 1525-7797 SP - 1 EP - 11 PB - American Chemical Society AN - OPUS4-58074 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. A1 - Weidner, Steffen A1 - Meyer, A. T1 - Ring-expansion polymerization (REP) of L-lactide with cyclic tin catalysts – About formation of extended ring crystals and optimization of Tm and ΔHm N2 - L-Lactide was polymerized in bulk at 140 °C with three different cyclic tin catalysts and the time was varied from 1 d up to 14 d. The MALDI TOF spectra confirmed the formation of cyclic polylactides (PLAs) and displayed a characteristic change of peak intensity distribution with formation of a “saw tooth pattern”. This pattern confirms a previous hypothesis that cyclic PLAs tend to form crystallites with extended ring conformation and relatively smooth surface. This type of crystallites is formed under thermodynamic control by transesterification on the surface of the crystallites. In this way PLAs with extraordinarily high melting temperatures (Tm's up to 200.6 °C) and extraordinarily high melting enthalpy were obtained (ΔHm's up to 105 J g−1). These ΔHm values require a revision of the maximum ΔHm value calculated in the literature for ideal PLA crystals. KW - Polylactide KW - MALDI-TOF MS KW - ring-expansion polymerization PY - 2022 DO - https://doi.org/10.1016/j.polymer.2022.125516 SN - 0032-3861 VL - 263 SP - 125516 PB - Elsevier Ltd. AN - OPUS4-56338 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Somasundaram, S. K. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Emmerling, Franziska A1 - Krishnan, S. A1 - Senthilkumar, K. A1 - Joseyphus, R.J. T1 - New insights into pertinent Fe-complexes for the synthesis of iron via the instant polyol process N2 - Chemically synthesized iron is in demand for biomedical applications due to its large saturation magnetization compared to iron oxides. The polyol process, suitable for obtaining Co and Ni particles and their alloys, is laborious in synthesizing Fe. The reaction yields iron oxides, and the reaction pathway remains unexplored. This study shows that a vicinal polyol, such as 1,2-propanediol, is suitable for obtaining Fe rather than 1,3-propanediol owing to the formation of a reducible Fe intermediate complex. X-ray absorption spectroscopy analysis reveals the ferric octahedral geometry and tetrahedral geometry in the ferrous state of the reaction intermediates in 1,2-propanediol and 1,3-propanediol, respectively. The final product obtained using a vicinal polyol is Fe with a γ-Fe2O3 shell, while the terminal polyol is favourable for Fe3O4. The distinct Fe–Fe and Fe–O bond lengths suggest the presence of a carboxylate group and a terminal alkoxide ligand in the intermediate of 1,2-propanediol. A large Fe–Fe bond distance suggests diiron complexes with bidentate carboxylate bridges. Prominent high-spin and low-spin states indicate the possibility of transition, which favors the reduction of iron ions in the reaction using 1,2-propanediol. KW - XAS KW - Nanoparticle PY - 2023 DO - https://doi.org/10.1039/D3CP01969A SN - 1463-9076 VL - 25 IS - 33 SP - 21970 EP - 21980 PB - Royal Society of Chemistry (RSC) AN - OPUS4-58073 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Surov, A. A1 - Vasilev, N. A1 - Voronin, A. A1 - Churakov, A. A1 - Emmerling, Franziska A1 - Perlovich, G. T1 - Ciprofloxacin salts with benzoic acid derivatives: structural aspects, solid-state properties and solubility performance N2 - n this work, three new pharmaceutical hydrated salts of ciprofloxacin with selected derivatives of benzoic acid, namely 4-hydroxybenzoic acid, 4-aminobenzoic acid and gallic acid, were obtained and systematically investigated by several solid-state analytical techniques. In situ Raman spectroscopy was applied to elucidate the alternative pathways of the solid forms' formation under mechanochemical conditions. Crystal structure analysis and a CSD survey allowed us to establish a distinct supramolecular motif formed by infinite columnar stacks of ciprofloxacin dimers arranged in the “head-to-tail” manner. An alternative “head-to-head” packing arrangement was only observed in the crystal of the hydrated ciprofloxacin salt with 4-aminobenzoic acid. In addition, the pH-solubility behavior of the solid forms was thoroughly investigated. Furthermore, a distinct structure–property relationship between the specific features of the supramolecular organization of the hydrated salts and their solubility was observed and discussed. KW - Mechanochemistry KW - XRD PY - 2020 DO - https://doi.org/10.1039/D0CE00514B VL - 22 IS - 25 SP - 4238 EP - 4249 AN - OPUS4-51818 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Altmann, Korinna T1 - Deliverable 2: Summary report on: The development of pristine SI traceable reference materials for SMPs (0.1 μm - 10 μm) and NPs (< 0.1 μm), representative of partially degraded/naturally aged samples in complex food and environmental matrices, and for realistic polydisperse size distributions and irregular shapes N2 - PlasticTrace aims to address the urgent need for development and harmonisation of methods for the chemical identification, physical characterisation and quantification of released small micro/nanoplastics (SMPs/NPs) in drinking water, food and environmental matrices, as required by the EU’s Circular Economy Action Plan (CEAP). This report describs the characterisation of nanoPP analysed in the PlasticTrace project aiming to develop a reference material. The nanoPP was analysed mainly by light scattering methods. Homogeneity control was done by DLS. KW - Nanoplastics KW - Reference materials PY - 2024 N1 - Project Number 21GRD07: PlasticTrace (Tracing Micro and NanoPlastics in Food and Environment), funded by the European Union SP - 1 EP - 29 PB - European Association of National Metrology Institutes (EURAMET) CY - Braunschweig AN - OPUS4-62299 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Alić Stolar, Jasna T1 - Harnessing Mechanochemistry to Combat PFAS Contamination N2 - For over 70 years, the uncontrolled production, use, and disposal of per- and polyfluoroalkyl substances (PFAS) have led to widespread global contamination, necessitating the rapid development of innovative and efficient remediation technologies. State-of-the-art strategies rely on energy-intensive incineration, which releases greenhouse gases and smaller, volatile PFAS derivatives. Here, we present a fast, simple, and sustainable method for the complete degradation of PFAS leveraging mechanochemistry to break down the persistent carbon-fluorine bonds. Our findings indicate that liquid-assisted grinding conditions accelerate the degradation of perfluorooctanoic acid compared to neat grinding conditions, resulting in a significant reduction in energy consumption. Moreover, the fluoride released during the process binds to inorganic additives, allowing fluorine recovery as crystalline salts and preventing the formation of secondary toxic waste. The method has strong potential for scaling up and offers a green and viable solution for real-world application in PFAS decontamination. T2 - International Conference on Sustainable Chemistry for Net Zero (ICSC-NZ) CY - St. Andrews, Scotland DA - 10.06.2025 KW - Mechanochemistry KW - PFAS KW - Remediation PY - 2025 AN - OPUS4-63971 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Goswami, Juli Nanda A1 - Haque, Najirul A1 - Seikh, Asiful H. A1 - Bhattacharya, Biswajit A1 - Emmerling, Franziska A1 - Bar, Nimai A1 - Ifseisi, Ahmad A. A1 - Biswas, Surajit A1 - Dolai, Malay T1 - Carboxylative cyclization of propargyl alcohols with carbon dioxide for the synthesis of α-alkylidene cyclic carbonates in presence of Co(III) schiff base complex catalyst N2 - A cobalt(III) complex, [Co(L)3](DMF) (1) of Schiff base ligand HL, 2-((E)-(benzylimino)methyl)-4-bromophenol is prepared and single crystal X-ray structural analysis have also been performed. The structures of complex 1 showed hexa-coordinated mononuclear systems that adopt octahedral geometry. The complex has also exhibited the supramolecular networks through non-covalent interactions like H-bonding, C–Hπ stacking. Moreover, the complex 1 is very effective in the catalytic fixation of carbon dioxide in propergyl alcohols to produce α-alkylidene cyclic carbonates. The catalytic production of α-alkylidene cyclic carbonates have been carried out through carboxylative cyclization of propargyl alcohols using CO2 balloon of 1 atm pressure at 80 ◦C. Solvent free condition (green synthesis) made this catalytic protocol eco-friendly towards the environment. Utilizing various substrates of propargyl alcohols moderate to high percentage yield (62–95%) of respective α-alkylidene cyclic carbonates product have been isolated over this catalytic reaction. Besides, the theoretical calculations (DFT) was performed for the prediction of probable mechanism of the catalytic reaction KW - Catalytic fixation of carbon dioxide KW - Carboxylative cyclization of propargyl alcohols KW - Cobalt (III) Schiff base complex KW - X-ray crystal analysis PY - 2024 DO - https://doi.org/10.1016/j.molstruc.2023.136868 SN - 0022-2860 VL - 1296 IS - Part 1 SP - 1 EP - 8 PB - Elsevier B.V. AN - OPUS4-58947 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Karafiludis, Stephanos A1 - Stawski, Tomasz T1 - Deciphering the non-classical Crystallization of transition metal phosphates (TMP) N2 - A crucial aspect of ensuring sustainable raw material utilization to meet global demand lies in the efficient recovery and reuse of critical elements and compounds. Phosphate, PO43-, and many transition metals e.g. Ni and Co are listed as critical raw materials (CRMs) due to their indispensable role in numerous industrial processes. However, these elements can also exert harmful environmental impacts, with phosphorus being a major contributor to anthropogenic eutrophication and transition metal ions acting as toxic pollutants, particularly in ground- and wastewaters. Typically, separate pathways have been considered to extract hazardous substances such as transition metals or phosphate, independently from each other. Here, we report the crystallization pathways of transition metal phosphate (TMP) compounds, M-struvite and M-phosphate octahydrate with M = Ni2+, Co2+, NixCo1-x2+, NH4MPO4∙6H2O, M3(PO4)2∙8H2O from aqueous solutions. The co-precipitation of these particular TMP compounds from industrial and agricultural wastewaters has high potential as a P- and 3d metal recovery route. For efficient extraction and transformation of the TMPs, a comprehensive understanding of their nucleation and crystallization pathways from aqueous solutions is required. While the crystallization mechanisms of magnesium or calcium phosphate-bearing phases have been researched for many decades (e.g. struvite, apatite), investigations into TMP materials are relatively scarce and often focus on the adsorption of transition metals on the surface instead of their actual incorporation in minerals. In our study, we investigated in detail the precipitation process of several Co and Ni phosphates using ex- and in-situ spectroscopic-, spectrometric- and diffraction-/scattering-based techniques. We show that the crystallization behavior of TMPs, indeed deviates from a classical crystallization paradigm and follows a non-classical multi-step pathway. Our work extends the understanding of TMP crystallization by elucidating the formation of amorphous precursors preceding the final crystalline phase This time-dependent transition of the transition metal precursor phases can be observed by electron-imaging/tomography depicting a progressively changing amorphous solids until their ultimate reconfiguration to a crystal (Figure 1). Here, the two-metallic NixCo1-x-mixtures deviated anomalously in their reaction kinetics, crystallization outcome and participation of both metals from their pure endmembers. By measuring the crystallization with in-situ X-ray scattering and pH using a flow-through setup geometry, a complex prolonged interplay among nucleating entities e.g. and amorphous or crystalline solids could be observed in the metal phosphate mixtures reaching equilibrium after almost two and a half hours (Figure 2). Our results provide a holistic perspective on the crystallization behavior of transition metal phosphate phases, shedding light on their unique nucleation and growth kinetics involving structural and chemical transformations of the intermediate phases. T2 - Granada Münster Discussion Meeting 2023 CY - Münster, Germany DA - 29.11.2023 KW - Non-classical crystallization theory KW - Transition metals KW - Phosphates PY - 2023 AN - OPUS4-59007 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Roy, Arkendu T1 - Hydroxide Based High Entropy MOF for Oxygen Evolution Reaction N2 - The energy crisis becomes more prominent in higher altitude countries like Germany, with higher annual energy demand. Thus, the generation of higher energy density fuel like hydrogen from renewable resources become the only way to solve the zero-emission energy system while avoiding the expensive batteries as an energy storage option. Therefore, water electrolysis cells to produce hydrogen and oxygen by storing of solar/wind energy in chemical bonds is a fruitful alternative for renewable and long-term energy generation. Thus, designing inexpensive water-splitting electrocatalyst material becomes a field of research of utmost importance. High entropy metal hydroxide organic frameworks (HE-MHOFs) are composed of high entropy hydroxide layer inside MOFs, resulting in a high degree of structural complexity and diversity than conventional MOFs. The concept of ‘high entropy’ refers to multiple types of metal ions (Metal = TM) in a near equimolar ratio in the same framework, creating a high degree of disorder and many possible structural configurations. Here, the HE-MHOF successfully synthesized by a conventional solvothermal process, crystallizes in the single phase with significant lattice distortion. A special-quasi-random (SQS) structure was simulated with equimolar compositions (~20% TM = Mn, Co, Ni, Cu and Zn) and a comparison was made with the ICP-AES (inductively coupled plasma atomic emission spectroscopy), XANES (X-ray absorption near edge structure) and XAFS (X-ray absorption fine structure) observations. Further, the elemental mapping (Energy dispersive Spectroscopy) of HE-MHOF shows the presence of all five different metals in the same crystallite to substantiate the ‘high entropy’ state of the MOF. The HE-MHOF offers improved thermal stability than mono-metallic MHOF and exhibit unique properties compared to traditional monometallic (Ni2+) MOF variants. Firstly, to elucidate the effect of the multimetallic system on the catalytic performance, we have performed density functional theory (DFT) calculations to investigate pre-redox cycles involved in the catalytic activation of HE (and Ni)-MOFs. HE-MHOF is further investigated as an electrocatalyst for oxygen evolution reaction (OER) due to its special high entropy hydroxide layered structure and electronic properties. Our DFT results have examined the traditional proton-coupled electron transfer (PCET) steps involving the single transition-metal site. The scrutiny of d-band centers and their behaviour in catalytic upgradation is investigated with density of states (DOS) analysis. It exhibits outstanding performance towards oxygen evolution reaction (OER) comparable to the experimental findings, which is also comparable to state-of-the-art OER catalysts based on precious metals such as iridium oxide and platinum carbon. We have considered different electrolyte solutions to elucidate the fast kinetics oxygen evolution reaction in the presence of various external nucleophilic anions. In hydroxyl-based MOFs, electrolytes' influence can substantially enhance catalytic activities. Here, with the help of DFT simulations, we have investigated the effect of the nucleophilicity of anion on each elementary reaction involved in the PCET mechanism of OER. T2 - EuroMOF 2023 CY - Granada, Spain DA - 24.09.2023 KW - Metal-organic Framework KW - High Entropy Materials KW - Electrocatalysis PY - 2023 AN - OPUS4-58971 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gugin, Nikita T1 - Optimizing the Green Synthesis of ZIF-8 by Reactive Extrusion Using In Situ Raman Spectroscopy N2 - ZIF-8 is a prominent member of the zeolitic imidazolate frameworks (ZIFs) subfamily of MOFs which possesses high thermal, chemical, and mechanical stabilities. Different routes have been explored to achieve the large-scale production of ZIF-8. However, these synthetic procedures are often inconsistent with the principles of sustainable chemical manufacturing. Aimed at developing scalable and greener production of ZIF-8, we adapted our previously reported in-batch „mix and wait“ synthesis[2] to continuous extrusion. To optimize the process, in-situ Raman spectroscopy was applied. Finally, we developed a simple and comprehensive approach to evaluating the environmental friendliness and scalability of MOF syntheses in view of their large-scale production. The synthesis of ZIF-8 was performed using a twin-screw extruder ZE 12 HMI equipped with an automatic volumetric feeder ZD 12B (Three-Tec GmbH, Switzerland) and peristaltic pump BT-L (Lead Fluid, China). The process was monitored in six different zones using a Raman RXN1TM analyzer (Kaiser Optical Systems, France) with a non-contact probe head. PMMA screw-in parts, which are transparent to Raman laser radiation, were specially manufactured to provide the laser focus within the barrel. PXRD, TGA, N2 adsorption measurements, and SEM were used as complementary techniques to characterize the extrudates. The batch ‘mix and wait’ synthesis of ZIF-8, consisting of bringing solid basic zinc carbonate and 2-methylimidazole in contact in a closed vial, was successfully adapted to reactive extrusion. The crystalline ZIF-8 continuously forms in the extruder under the mixing of solid reagents in the presence of a catalytic amounts of H2O or EtOH. The temperature, type of liquid, feeding rate, and excess of linker were optimized using in situ Raman spectroscopy. Pure and highly crystalline ZIF-8 was isolated at 40 °C by adding a catalytic amount of EtOH and a linker excess of 25%. The resulting material has excellent porosity with the BET surface area slightly exceeding that of the reference Basolite® Z1200 (1816 vs. 1734 m2 g–1). The reaction could yield ~ 3 kg d–1 assuming a continuous operation, with a space-time yield of ca. 67,000 kg m–3 d–1. The present method was compared to the published pathways based on Green Chemistry principles and proved to have the highest potential for large-scale production of ZIF-8. T2 - 5th European Conference on Metal Organic Frameworks and Porous Polymers (EuroMOF2023) CY - Granada, Spain DA - 24.09.2023 KW - In situ Raman KW - Reactive extrusion KW - Green chemistry KW - Mechanochemistry KW - MOFs KW - Large-scale synthesis PY - 2023 AN - OPUS4-58950 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gugin, Nikita T1 - Chemists have solutions and know how to get rid of them N2 - Metal-organic framework-based biocomposites (MOF-biocomposites) are promising materials for biosensing, biocatalysis, and delivery of biopharmaceuticals. One of the most studied MOFs for bioapplications is ZIF-8 (zeolitic imidazolate framework 8) due to its high surface area, high thermal and chemical stability, and low cytotoxicity. The conventional synthesis of ZIF-8-biocomposites called biomimetic mineralization includes mixing selected biomolecules 2-methylimidazole, and soluble Zn2+ source in water.[3] Despite the high efficiency of the method, it does not allow for large-scale production and is restricted to hydrophilic biomolecules. Aimed at developing a scalable and versatile approach, we adapted our recently-reported ZIF-8 reactive extrusion for biocomposite production. We selected bovine serum albumin (BSA) as an inexpensive model biomacromolecule for the preparation of biocomposites. The synthesis of BSA@ZIF-8 was performed using a twin-screw extruder ZE 12 HMI (Three-Tec Gmbh) at a mild temperature of 40 °C. Automatic volumetric feeder ZD 12B (Three-Tec GmbH) was used to supply the reagent mixture consisting of 2-methylimidazole, zinc source, and BSA. To initiate the reaction, a catalytic amount of EtOH was added using a peristaltic pump BT-L (Lead Fluid, China). Powder X-Ray diffraction (PXRD), thermogravimetric analysis (TGA), FTIR, and N2 adsorption were used to characterize the extrudates. Highly crystalline and pure BSA@ZIF-8 with different BSA loadings was isolated after washing the extrudate with EtOH and sodium dodecyl sulfate. The EtOH feeding rate was optimized by following the protein encapsulation efficiency at a BSA mass fraction of 10%. A continuous extruder operation under optimized conditions showed good reproducibility and capability of producing biocomposites on the kilograms scale. These results provide highly valuable information for cheap and large-scale production of ZIF-8-based biocomposites. Due to the lack of restrictions on molecule size and solubility, our proof-of-concept study may significantly expand the selection of biomolecules for immobilization in ZIF-8, making the method applicable to various functional applications T2 - SALSA Make and Measure conference CY - Berlin, Germany DA - 13.09.2023 KW - In situ Raman KW - Large-scale processing KW - Reactive extrusion KW - Large-scale production KW - Mechanochemistry PY - 2023 AN - OPUS4-58953 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gugin, Nikita A1 - Schwab, Alexander T1 - Reactive extrusion of a model BSA@ZIF-8 biocomposite: a scalable, continuous and sustainable approach N2 - Metal-organic framework-based biocomposites (MOF-biocomposites) are promising materials for biosensing, biocatalysis, and delivery of biopharmaceuticals. One of the most studied MOFs for bioapplications is ZIF-8 (zeolitic imidazolate framework 8) due to its high surface area, high thermal and chemical stability, and low cytotoxicity. The conventional synthesis of ZIF-8-biocomposites called biomimetic mineralization includes mixing selected biomolecules 2-methylimidazole, and soluble Zn2+ source in water. Despite the high efficiency of the method, it does not allow for large-scale production and is restricted to hydrophilic biomolecules. Aimed at developing a scalable and versatile approach, we adapted our recently-reported ZIF-8 reactive extrusion for biocomposite production. We selected bovine serum albumin (BSA) as an inexpensive model biomacromolecule for the preparation of biocomposites. The synthesis of BSA@ZIF-8 was performed using a twin-screw extruder ZE 12 HMI (Three-Tec Gmbh) at a mild temperature of 40 °C. Automatic volumetric feeder ZD 12B (Three-Tec GmbH) was used to supply the reagent mixture consisting of 2-methylimidazole, zinc source, and BSA. To initiate the reaction, a catalytic amount of EtOH was added using a peristaltic pump BT-L (Lead Fluid, China). Powder X-Ray diffraction (PXRD), thermogravimetric analysis (TGA), FTIR, and N2 adsorption were used to characterize the extrudates. Highly crystalline and pure BSA@ZIF-8 with different BSA loadings was isolated after washing the extrudate with EtOH and sodium dodecyl sulfate. The EtOH feeding rate was optimized by following the protein encapsulation efficiency at a BSA mass fraction of 10%. A continuous extruder operation under optimized conditions showed good reproducibility and capability of producing biocomposites on the kilograms scale. These results provide highly valuable information for cheap and large-scale production of ZIF-8-based biocomposites. Due to the lack of restrictions on molecule size and solubility, our proof-of-concept study may significantly expand the selection of biomolecules for immobilization in ZIF-8, making the method applicable to various functional applications T2 - Tag der Chemie 2023 CY - Berlin, Germany DA - 05.07.2023 KW - Biocomposite KW - MOFs KW - Reactive extrusion KW - Zeolitic imidazolate framework PY - 2023 AN - OPUS4-58949 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gugin, Nikita T1 - Mixing Reactions Enable Green Synthesis of ZIF-8 at Large Scale: Batch and Continuous Modes N2 - We report the scale-up of a batch solid synthesis of zeolitic imidazolate framework-8 (ZIF-8) for reactive extrusion. The crystalline product forms in the extruder directly under the mixture of solid 2-methylimidazole and basic zinc carbonate in the presence of a catalytic amount of liquid. The process parameters such as temperature, liquid type, feeding rate, and linker excess were optimized using the setup specifically designed for in situ Raman spectroscopy. Highly crystalline ZIF-8 with a Brunauer–Emmett–Teller (BET) surface area of 1816 m2 g–1 was quantitatively prepared at mild temperature using a catalytic amount of ethanol and a small excess of the linker. Finally, we developed a simple and comprehensive approach to evaluating the environmental friendliness and scalability of metal–organic framework (MOF) syntheses in view of their large-scale production. T2 - 2023 #RSCPoster Twitter Conference CY - Online meeting DA - 28.02.2023 KW - MOFs KW - Green chemistry KW - Reactive extrusion KW - Large-scale production KW - Mechanochemistry KW - Zeolitic imidazolate framework PY - 2023 UR - https://twitter.com/NikitaGugin/status/1630538555675099139 AN - OPUS4-58951 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gugin, Nikita T1 - Large-Scale Synthesis of ZIF-8 for Hydrogen Storage: Batch and Continuous Modes N2 - We report the scale-up of a batch solid synthesis of zeolitic imidazolate framework-8 (ZIF-8) for reactive extrusion. The crystalline product forms in the extruder directly under the mixture of solid 2-methylimidazole and basic zinc carbonate in the presence of a catalytic amount of liquid. Highly crystalline ZIF-8 with a Brunauer−Emmett−Teller (BET) surface area of 1816 m2 g−1 was quantitatively prepared at mild temperature using a catalytic amount of ethanol and a small excess of the linker. Extruded ZIF-8 is an affordable alternative to commercial Basolite Z1200 as a reference material for H2 cryoadsorption. T2 - Metrology for Advanced Hydrogen Storage Solutions (MefHySto) Closing Conference CY - Berlin, Germany DA - 03.07.2023 KW - In situ Raman KW - Large-scale processing KW - Mechanochemistry KW - Twin-screw extrusion (TSE) PY - 2023 AN - OPUS4-58926 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pütz, E. A1 - Smales, Glen Jacob A1 - Jegel, O. A1 - Emmerling, Franziska A1 - Tremel, W. T1 - Tuning ceria catalysts in aqueous media at the nanoscale: how do surface charge and surface defects determine peroxidase- and haloperoxidase-like reactivity N2 - Designing the shape and size of catalyst particles, and their interfacial charge, at the nanometer scale can radically change their performance. We demonstrate this with ceria nanoparticles. In aqueous media, nanoceria is a functional mimic of haloperoxidases, a group of enzymes that oxidize organic substrates, or of peroxidases that can degrade reactive oxygen species (ROS) such as H2O2 by oxidizing an organic substrate. We show that the chemical activity of CeO2−x nanoparticles in haloperoxidase- and peroxidaselike reactions scales with their active surface area, their surface charge, given by the ζ-potential, and their surface defects (via the Ce3+/Ce4+ ratio). Haloperoxidase-like reactions are controlled through the ζ-potential as they involve the adsorption of charged halide anions to the CeO2 surface, whereas peroxidase-like reactions without charged substrates are controlled through the specific surface area SBET. Mesoporous CeO2−x particles, with large surface areas, were prepared via template-free hydrothermal reactions and characterized by small-angle X-ray scattering. Surface area, ζ-potential and the Ce3+/Ce4+ ratio are controlled in a simple and predictable manner by the synthesis time of the hydrothermal reaction as demonstrated by X-ray photoelectron spectroscopy, sorption and ζ-potential measurements. The surface area increased with synthesis time, whilst the Ce3+/Ce4+ ratio scales inversely with decreasing ζ-potential. In this way the catalytic activity of mesoporous CeO2−x particles could be tailored selectively for haloperoxidase- and peroxidase-like reactions. The ease of tuning the surface properties of mesoporous CeO2x particles by varying the synthesis time makes the synthesis a powerful general tool for the preparation of nanocatalysts according to individual needs. KW - SAXS KW - Ceria KW - Zeta potential PY - 2022 DO - https://doi.org/10.1039/D2NR03172H SP - 1 EP - 12 PB - Royal Society of Chemistry AN - OPUS4-55649 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Altmann, Korinna T1 - Reference material candidates for microplastic analysis N2 - Every day, there are new headlines in the media about microplastics (1-1000 µm, ISO/TR 21960:2020) and nanoplastics (< 1 µm, ISO/TR 21960:2020) findings all over the planet with high variations in particle number and mass. The challenges in analytics are very complex, e.g. representative sampling, non-destructive sample preparation with concentrated particles and homogeneous distribution and true detection. All together lead to lacks in harmonization and results, which are hardly comparable. On the other hand, monitoring of microplastics is mandatory in the future strictly regulated by the EU commission in the Drinking water and Wastewater Framework Directive. One step to accurate and precise results will be the development of suitable reference materials mimicking particles in the environment. BAM developed test materials, which are produced by mixing a small portion of microplastic particles with a water-soluble matrix. After solid phase dilution and homogenisation small portions are pressed into tablets and bottled in glass vials (Figure 1). These tablets are well characterized with particle size distribution and SEM images. Additionally, they are tested as reference material candidate according to homogeneity and stability for particle number with µ-IR and µ-Raman as well as on particle mass with Py-GC/MS and TED-GC/MS after ISO Guide 35. Results are promising. The material passed the homogeneity control. No changes are observed within 6 months of storage. The same tested reference material is finally used in sample preparation experiments, where environmental suspended particular matter from surface water or baby milk powders are spiked with the tablets. T2 - ESOPS CY - Berlin, Germany DA - 09.09.2024 KW - Microplastics KW - TED-GC/MS KW - Reference materials KW - Polymer 3R KW - Tablets PY - 2024 AN - OPUS4-61017 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Miliūtė, Aistė T1 - Synthesis and phase purity of the negative thermal expansion material ZrV2O7 N2 - This repository contains computational and experimental data for the manuscript titled “Synthesis and phase purity of the negative thermal expansion material ZrV2O7”. KW - NTE KW - Sol-gel KW - Solid-state KW - Ab-initio KW - XRD KW - Raman PY - 2024 DO - https://doi.org/10.5281/zenodo.12688634 PB - Zenodo CY - Geneva AN - OPUS4-61360 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rautenberg, Max A1 - Bhattacharya, Biswajit A1 - Akhmetova, Irinia A1 - Emmerling, Franziska T1 - Mechanochemical and solution syntheses of two novel cocrystals of orcinol with two N,N0-Dipyridines: Structural diversity with varying ligand flexibility N2 - We studied the influence of coformers flexibility on the supramolecular assembly of 5-substituted resorcinol. Two cocrystals of orcinol (ORL) with two dipyridine molecules, i.e. 1,2-di(4-pyridyl)ethane (ORLeBPE) and 1,2-di(4-pyridyl)ethylene (ORLeBPY), were prepared by mechanochemical synthesis and slow evaporation of solvent. The new crystalline solids were thoroughly characterized by single crystal Xray diffraction (SCXRD), powder X-ray diffraction analysis (PXRD), Fourier-transform infrared spectroscopy (FT-IR), differential thermal analysis (DTA), and thermogravimetric analysis (TGA). Structural determination reveals that in both cocrystals, the phenolepyridine, i.e. OeH/N(py) heterosynthon takes the main role in the formation of cocrystals. In ORLeBPE, the components form infinite 1D zig-zag chains, which are extended to 2D layer structure by inter-chain CeH/O interactions between BPE hydrogen atoms and hydroxyl oxygen atoms of ORL. In ORLeBPY, the components form a 0D fourcomponent complex. Formation of the discrete assemblies is attributed to the comparative rigid nature of BPY, which restricts the formation of an extended network. KW - Cocrystal KW - Single crystal KW - X-ray diffraction KW - Mechanochemistry PY - 2020 DO - https://doi.org/10.1016/j.molstruc.2020.128303 SN - 0022-2860 VL - 1217 SP - 128303 PB - Elsevier B.V. AN - OPUS4-51023 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Opitz, P. A1 - Besch, L. A1 - Panthöfer, M. A1 - Kabelitz, Anke A1 - Unger, R. A1 - Emmerling, Franziska A1 - Mondeshki, M. A1 - Tremel, W. T1 - Insights into the In Vitro Formation of Apatite from Mg‐Stabilized Amorphous Calcium Carbonate N2 - A protein‐free formation of bone‐like apatite from amorphous precursors through ball‐milling is reported. Mg2+ ions are crucial to achieve full amorphization of CaCO3. Mg2+ incorporation generates defects which strongly retard a recrystallization of ball‐milled Mg‐doped amorphous calcium carbonate (BM‐aMCC), which promotes the growth of osteoblastic and endothelial cells in simulated body fluid and has no effect on endothelial cell gene expression. Ex situ snapshots of the processes revealed the reaction mechanisms. For low Mg contents (<30%) a two phase system consisting of Mg‐doped amorphous calcium carbonate (ACC) and calcite “impurities” was formed. For high (>40%) Mg2+ contents, BM‐aMCC follows a different crystallization path via magnesian calcite and monohydrocalcite to aragonite. While pure ACC crystallizes rapidly to calcite in aqueous media, Mg‐doped ACC forms in the presence of phosphate ions bone‐like hydroxycarbonate apatite (dahllite), a carbonate apatite with carbonate substitution in both type A (OH−) and type B (PO43−) sites, which grows on calcite “impurities” via heterogeneous nucleation. This process produces an endotoxin‐free material and makes BM‐aMCC an excellent “ion storage buffer” that promotes cell growth by stimulating cell viability and metabolism with promising applications in the treatment of bone defects and bone degenerative diseases. KW - Total Scattering KW - XRD KW - Mechanochemistry PY - 2020 DO - https://doi.org/10.1002/adfm.202007830 VL - 31 IS - 3 SP - 7830 PB - Wiley VHC-Verlag AN - OPUS4-51761 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Altmann, Korinna T1 - Challenges in microplastics standardisation N2 - This talk addresses the challanges in microplastic analytics. It shows the need of standards, analytics and reference materials for accurate and reliable measurements. It explains the state of the art for referenence materials in this field and their problems. A solution is presented with PET tablets. The urgent need of harmonisation it also emphasised. T2 - MARII Summit CY - Madrid, Spain DA - 15.10.2025 KW - Microplastics KW - Reference materials PY - 2025 AN - OPUS4-64488 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gugin, Nikita T1 - Advancing Industrial Mechanochemistry: Real-Time Insights for Sustainable, Solvent-Free Manufacturing N2 - Mechanochemistry is an environmentally friendly synthetic approach that enables the sustainable production of a wide range of chemicals while reducing or eliminating the need for solvents. Reactive extrusion aims to move mechanochemistry from its conventional gram-scale batch reactions, typically performed in laboratory ball mills, to a continuous, large-scale process. Meeting this challenge requires in situ monitoring techniques to gain insights into reactive extrusion and its underlying processes. While the effectiveness of in situ Raman spectroscopy in providing molecular-level information has been demonstrated, our study uses energy-dispersive X-ray diffraction to monitor reactive extrusion in real time at the crystalline level. Our results provide previously unavailable control over thereactiveextrusion process, promoting its perception as an industrially feasible green alternative to traditional solventbased syntheses. T2 - #RSCPoster 2025 CY - Online meeting DA - 04.03.2025 KW - Mechanochemistry PY - 2025 AN - OPUS4-63803 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Alić Stolar, Jasna T1 - Harnessing mechanochemistry to combat PFAS contamination N2 - For over 70 years, the uncontrolled production, use, and disposal of per- and polyfluoroalkyl substances (PFAS) have led to widespread global contamination, necessitating the rapid development of innovative and efficient remediation technologies. State-of-the-art strategies rely on energy-intensive incineration, which releases greenhouse gases and smaller, volatile PFAS derivatives. Here, we present a fast, simple, and sustainable method for the complete degradation of PFAS leveraging mechanochemistry to break down the persistent carbon-fluorine bonds. Our findings indicate that liquid-assisted grinding conditions accelerate the degradation of perfluorooctanoic acid compared to neat grinding conditions, resulting in a significant reduction in energy consumption. Moreover, the fluoride released during the process binds to inorganic additives, allowing fluorine recovery as crystalline salts and preventing the formation of secondary toxic waste. The method has strong potential for scaling up and offers a green and viable solution for real-world application in PFAS decontamination. T2 - International Conference on Sustainable Chemistry for Net Zero (ICSC-NZ) CY - St. Andrews, Scotland DA - 10.06.2025 KW - Mechanochemistry KW - PFAS KW - Remediation PY - 2025 AN - OPUS4-63970 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Alić Stolar, Jasna T1 - Harnessing mechanochemistry to combat PFAS contamination N2 - For over 70 years, the uncontrolled production, use, and disposal of per- and polyfluoroalkyl substances (PFAS) have led to widespread global contamination, necessitating the rapid development of innovative and efficient remediation technologies. State-of-the-art strategies rely on energy-intensive incineration, which releases greenhouse gases and smaller, volatile PFAS derivatives. Here, we present a fast, simple, and sustainable method for the complete degradation of PFAS leveraging mechanochemistry to break down the persistent carbon-fluorine bonds. Our findings indicate that liquid-assisted grinding conditions accelerate the degradation of perfluorooctanoic acid compared to neat grinding conditions, resulting in a significant reduction in energy consumption. Moreover, the fluoride released during the process binds to inorganic additives, allowing fluorine recovery as crystalline salts and preventing the formation of secondary toxic waste. The method has strong potential for scaling up and offers a green and viable solution for real-world application in PFAS decontamination. T2 - The International Symposium on Mechanochemistry (Mech’cheM 2025) CY - Montpellier, France DA - 04.06.2025 KW - Mechanochemistry KW - PFAS PY - 2025 AN - OPUS4-63956 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Moss, Caitlin T1 - Framework Materials for the Electrocatalytic Reduction of Nitrate to Ammonia N2 - The electrocatalytic reduction of nitrate to ammonia offers a sustainable alternative to the energy-intensive Haber-Bosch process while simultaneously addressing the pressing issue of nitrate pollution in water sources. Developing efficient catalysts for this reaction is therefore vital for both environmental remediation and green ammonia production. Framework materials such as metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and coordination polymers present an emerging class of electrocatalytic materials due to their high surface area, tunable porosity, and structural modularity. Their ability to incorporate diverse metal centers and functional groups makes them promising candidates for selective and efficient nitrate reduction. In order to change and improve catalytic properties, different synthesis strategies can be pursued, such as metal alloying or calcination under different conditions. To fully understand and optimize these materials, advanced characterization techniques are essential to correlate structural features with catalytic performance, alongside in-situ methods for real-time mechanistic insights. T2 - Tag der Chemie 2025 CY - Berlin, Germany DA - 03.07.2025 KW - Electrocatalysis KW - Electrochemisty KW - Framework Materials KW - Ammonia Synthesis KW - Nitrate Reduction PY - 2025 AN - OPUS4-63815 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmalz, Alina T1 - Framework Materials for the Electrocatalytic Reduction of Nitrate to Ammonia N2 - The electrocatalytic reduction of nitrate to ammonia offers a sustainable alternative to the energy-intensive Haber-Bosch process while simultaneously addressing the pressing issue of nitrate pollution in water sources. Developing efficient catalysts for this reaction is therefore vital for both environmental remediation and green ammonia production. Framework materials such as metal-organic frameworks (MOFs) or metalated covalent organic frameworks (COFs) present an emerging class of electrocatalytic materials due to their high surface area, tunable porosity, and structural modularity. Their ability to incorporate diverse metal centers and functional groups makes them promising candidates for selective and efficient nitrate reduction. In order to change and improve catalytic properties, different synthesis strategies can be pursued, such as metal alloying, doping or calcination. To fully understand and optimize these materials, advanced characterization techniques are essential to correlate structural features with catalytic performance, alongside in-situ methods for real-time mechanistic insights. T2 - 10th European Crystallography School CY - Ohrid, North Macedonia DA - 23.06.2025 KW - Electrocatalysis KW - Electrochemistry KW - Framework Materials KW - Ammonia Synthesis KW - Nitrate Reduction PY - 2025 AN - OPUS4-63846 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ryll, Tom William T1 - In-situ analysis of nucleation processes – case study: calciumsulfate N2 - In this project we investigate nucleation pathways by utilizing synchrotron-XRD and running a case-study on calcium sulfate and its polymorphs. To accomplish this, we developed a modular automation setup for reactions in solution to run synthesis and control reaction conditions. So far we successfully characterized the recycling process of gypsum (CaSO4*2H2O) and are now investigating the formation of anhydrite (CaSO4*0H2O) as well as possible applications for the automation setup and analysis. T2 - SALSA Make & Measure 2025 CY - Berlin, Germany DA - 10.09.2025 KW - Recycling KW - Gypsum KW - Synchrotron-X-ray-diffraction KW - Raman-spectroscopy KW - Automation PY - 2025 AN - OPUS4-64135 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - INPR A1 - Smales, Glen J. A1 - Appel, Paul Alexander A1 - Breßler, Ingo A1 - Chambers, Aaron A1 - Dumele, Oliver A1 - Ebisch, Maximilian A1 - Frontzek, Julius A1 - del Refugio Monroy, José A1 - Rosalie, Julian M. A1 - Pauw, Brian R. T1 - DACHS and RoWaN: The Automated and Traceable Synthesis of ZIF-8 N2 - Automated synthesis and open-data practices are increasingly seen as key enablers of transparent, traceable, and reproducible science. By combining automation with structured, metadata-rich documentation, it becomes possible to systematically com- pare synthesis strategies and link outcomes to detailed parameters. In this work, we implement such an approach to study the synthesis of ZIF-8, comparing hand and automation-assisted methods under controlled conditions. Using over 100 synthesis experiments, we assess the repeatability of particle size and yield, and explore how variations in mixing and injection influence outcomes. This study demonstrates how traceable synthesis workflows can support repeatability and comparison across synthe- sis strategies. The DACHS (Database for Automation, Characterization and Holistic Synthesis) framework underpins this work, providing a lightweight infrastructure for transparent synthesis data capture. KW - Automation KW - MOFs KW - SAXS PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645861 DO - https://doi.org/10.26434/chemrxiv-2025-7fgg0 SP - 1 EP - 32 PB - Cambridge AN - OPUS4-64586 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pauw, Brian Richard T1 - Getting down to business: pragmatic solutions for laboratory automation N2 - A chemical engineer by training, Brian drifted towards physics and now focuses on a broad spectrum of activities with the aim to improve scientific reproducibility. This includes studies on holistically improving data quality, data collection efficiency and traceability, as well as concomitant laboratory automation for the preparation of consistent, well-documented sample series. The need for pragmatism led to an inexpensive, flexible laboratory automation platform that can be implemented in a modest amount of time. This talk presents that effort. T2 - Future Labs Live 2024 CY - Basel, Switzerland DA - 25.06.2024 KW - Laboratory automation KW - Experiment tracking KW - Holistic experimentation KW - Experimental traceability KW - Data visualisation KW - Parameter correlation. PY - 2024 AN - OPUS4-60583 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pauw, Brian Richard T1 - Glimpses of the future: a “full stack”, highly automated materials research laboratory N2 - In our (dramatically understaffed) X-ray scattering laboratory, developing a systematic, holistic methodology let us provide scattering and diffraction information for more than 2100 samples for 200+ projects led by 120+ collaborators. Combined with automated data correction pipelines, and our analysis and simulation software, this led to more than 40 papers in the last 5 years with just over 2 full-time staff members. This year, our new, modular synthesis platform has made more than 1000 additional samples for us to analyse and catalogue. By virtue of the automation, the synthesis of these samples is automatically documented in excruciating detail, preparing them for upload and exploitation in large-scale materials databases. Having developed these proof-of-concepts, we find that materials research itself is changed dramatically by automating dull tasks in a laboratory. This talk is intended to spark ideas and collaborations by providing an overview of: 1) the current improvements in our scattering laboratory methodology, 2) introducing our open, modular robotic platform that is used for systematic sample preparation, and 3) demonstrating the data structure of the synthesis logs and measurements. Finally, the remaining bottlenecks and points of attention across all three are highlighted. T2 - FAIRmat seminar CY - Berlin, Germany DA - 28.09.2023 KW - Data stewartship KW - Metadata collection KW - Laboratory methodology KW - MOUSE KW - Robotics KW - Lab automation KW - Holistic science PY - 2023 UR - https://www.fairmat-nfdi.eu/events/brian-pauw AN - OPUS4-58464 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sieg, Holger A1 - Heilscher, Jasmin A1 - Ott, Franziska A1 - Böhmert, Linda A1 - Drusch, Stephan A1 - Thünemann, Andreas A1 - Rohn, Sascha A1 - Braeuning, Albert A1 - Kieserling, Helena T1 - Direct Interactions of Micro- and Nanoplastics with Proteins – A Key to Mechanistic Understanding? N2 - Micro-/Nanoplastics (MNP) have gained widespread scientific and public attention within the last two decades. While knowledge about measuring techniques, occurrence and exposure was improved substantially, questions on toxicological impact of MNP remained unclear. A major reason for that are the continued remaining knowledge gaps with regard to mechanistical understanding of MNP effects. Our work aimed at investigating MNP properties, protein interactions, and cellular effects in combination. Therefore, we characterized MNP-protein- adsorption, changes in protein structure, cellular uptake and cellular modes of action. In a first study, we studied the molecular interactions of β-lactoglobulin, a serum and storage protein, with different MNP materials1. We identified structural changes, depending on physicochemical MNP properties, using FTIR- and fluorescence spectroscopy. Furthermore, we investigated cellular uptake of MNP individually and as a complex with β-lactoglobulin and studied the effects on cell growth and viability, using colorimetric MTT testing, flow cytometry, and cell impedance measurements. MNP material properties, especially hydrophobicity, had an impact on protein folding and consequently also on cellular interactions. In a second study, we applied α-amylase, an extracellular digestive protein with enzymatic activity. Here, in addition, we investigated the influence of MNP binding on enzyme activity, using a colorimetric starch degradation assay. We observed for the most MNP, that adsorption processes resulted in a decrease of enzyme activity. Furthermore, we used Alexa633 staining to visualize MNP uptake with and without the presence of α-amylase. Taken together, this work aims to close data gaps regarding mechanistical effects of MNP on cells by investigating direct MNP-protein-interactions. Mechanistic knowledge is crucial for understanding toxicological effects of MNP, and therefore, also for the risk assessment of possible hazards on human health. T2 - 92. Jahrestagung der Deutschen Gesellschaft für Experimentelle und Klinische Pharmakologie und Toxikologie (DGPT) CY - Düsseldorf, Germany DA - 17.03.2026 KW - Microplastics KW - Nanoplastics PY - 2026 AN - OPUS4-65667 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pauw, Brian Richard T1 - Chasing perfection: A holistic approach to materials science scattering experiments N2 - The materials scientists we work with do not want (or need) to learn the ways of the scatterer; they are primarily interested in obtaining trustworthy answers. In particular, they need structural understanding in light of the wider framework of their experiment(s). Our interest, therefore, lies in helping them attain this this interconnected understanding, while using such investigations to further hone our methodology to approximate perfection. While perfection is by definition an unattainable goal, we have spent the last 15+ years exploring and expanding on many of its constituent aspects (often together with likeminded people) [1]. These aspects include: - developing various visualization and simulation tools, - deconstructing data corrections and uncertainty estimation, - advancing analysis methods, - quantifying questions on traceability, documentation, - reproducible automation of synthesis-, measurement- and data pipelines, - data visualization, exploration and education, - and many more… T2 - XIX International Small Angle Scattering Conference CY - Taipei, Taiwan DA - 04.11.2024 KW - Methodology KW - X-ray scattering KW - Data quality KW - Data provenance KW - Data stewardship KW - Lab automation KW - Perfection PY - 2024 AN - OPUS4-61625 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Smales, Glen Jacob A1 - Pauw, Brian Richard T1 - DACHS/MOFs/AutoMOFs_2/Synthesis N2 - The DACHS (Database for Automation, Characterization and Holistic Synthesis) project aims to create completely traceable experimental data, covering syntheses, measurements, analyses, and interpretations. DACHS_MOFs focuses on the synthesis and characterisation of metal-organic frameworks, across multiple, automation-assisted experimental series (AutoMOFs), with the overall goal of producing reproducible MOF samples through tracking of the synthesis parameters. DACHS_MOFs is simultaneously used to test the DACHS principles. This upload contain synthesis data from AutoMOFs_2 in HDF5 format (.h5). Each .h5 file contains detailed information on the chemical, experimenal, and synthesis parameters used during the synthesis of a single AutoMOF sample. KW - Automation KW - Procedure KW - Synthesis KW - Traceability PY - 2024 DO - https://doi.org/10.5281/zenodo.11236074 PB - Zenodo CY - Geneva AN - OPUS4-60611 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pauw, Brian Richard T1 - A holistic experiment chain for scattering-powered materials science investigations N2 - In our (dramatically understaffed) X-ray scattering laboratory, developing a systematic, holistic methodology1 let us provide scattering and diffraction information for more than 2100 samples for 200+ projects led by 120+ collaborators over the last five years. Combined with universal, automat-ed data correction pipelines, as well as our analysis and simulation software, this led to more than 40 papers2 in the last 5 years with just over 2 full-time staff members. While this approach greatly improved the consistency of the results, the consistency of the samples and sample series provided by the users was less reliable nor necessarily reproducible. To address this issue, we built an EPICS-controlled, modular synthesis platform to add to our laboratory. To date, this has prepared over 1200 additional (Metal-Organic Framework) samples for us to meas-ure, analyse and catalogue. By virtue of the automation, the synthesis of these samples is automat-ically documented in excruciating detail, preparing them for upload and exploitation in large-scale materials databases alongside the morphological results obtained from the automated X-ray scat-tering analysis. Having developed these proof-of-concepts, we find that the consistency of results are greatly im-proved by virtue of their reproducibility, hopefully adding to the reliability of the scientific findings as well. Additionally, the nature of the experiments has changed greatly, with much more emphasis on preparation and careful planning. This talk will discuss the advantages and disadvantages of this highly integrated approach and will touch upon upcoming developments. T2 - canSAS-XIII CY - Grenoble, France DA - 16.10.2023 KW - Methodology KW - Lab automation KW - X-ray scattering KW - Automated synthesis KW - Data stewardship KW - Holistic experimental procedures KW - Scicat PY - 2023 AN - OPUS4-58643 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Diehn, S. A1 - Zimmermann, B. A1 - Tafintseva, V. A1 - Seifert, S. A1 - Bagcioglu, M. A1 - Ohlson, M. A1 - Weidner, Steffen A1 - Fjellheim, S. A1 - Kohler, A. A1 - Kneipp, Janina T1 - Combining Chemical Information From Grass Pollen in Multimodal Characterization N2 - The analysis of pollen chemical composition is important to many fields, including agriculture, plant physiology, ecology, allergology, and climate studies. Here, the potential of a combination of different spectroscopic and spectrometric methods regarding the characterization of small biochemical differences between pollen samples was evaluated using multivariate statistical approaches. Pollen samples, collected from three populations of the grass Poa alpina, were analyzed using Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, surface enhanced Raman scattering (SERS), and matrix assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS). The variation in the sample set can be described in a hierarchical framework comprising three populations of the same grass species and four different growth conditions of the parent plants for each of the populations. Therefore, the data set can work here as a model system to evaluate the classification and characterization ability of the different spectroscopic and spectrometric methods. ANOVA Simultaneous Component Analysis (ASCA) was applied to achieve a separation of different sources of variance in the complex sample set. Since the chosen methods and sample preparations probe different parts and/or molecular constituents of the pollen grains, complementary information about the chemical composition of the pollen can be obtained. By using consensus principal component analysis (CPCA), data from the different methods are linked together. This enables an investigation of the underlying global information, since complementary chemical data are combined. The molecular information from four spectroscopies was combined with phenotypical information gathered from the parent plants, thereby helping to potentially link pollen chemistry to other biotic and abiotic parameters. KW - Pollen KW - MALDI-TOF MS KW - FTIR KW - Raman KW - Multivariate analyses PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504822 DO - https://doi.org/10.3389/fpls.2019.01788 VL - 10 SP - 1788 AN - OPUS4-50482 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen T1 - The Ring-Opening Polymerisation-Polycondensation (ROPPOC) Approach to cyclic Polymers N2 - A new concept called “Ring-Opening Polymerization (ROP) combined with simultaneous POlyCondensation” (ROPPOC) is presented and discussed. This synthetic strategy is based on the intermediate formation of chains having two end groups that can react with each other. The ROPPOC syntheses are subdivided into three groups according to the nature of the chain ends: two ionic end groups, one ionic and one covalent chain end and a combination of two reactive covalent end groups may be involved, depending on the catalyst. The usefulness for the preparation of cyclic polymers is discussed with a review of numerous previously published examples. These examples concern to following classes of cyclic polymers: polypeptides, polyamides, polyesters, including polycarbonates, and cyclic polysiloxanes. It is demonstrated, that the results of certain ROPPOC syntheses are in contradiction to the Jacobson-Stockmayer theory. Finally, the usefulness of ROPPOCs for the detection of polydisperse catenanes is discussed. KW - Ring-opening Polymerisation KW - MALDI-TOF MS KW - ROPPOC KW - Cyclic PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508509 DO - https://doi.org/10.1002/marc.202000152 SP - 2000152 PB - Wiley AN - OPUS4-50850 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen A1 - Meyer, A. T1 - High Tm poly(L-lactide)s via REP or ROPPOC of L-lactide N2 - A new kind of high melting (HTm) pol(L-lactide) was discovered when cyclic poly(L-lactide)s were prepared by ring-expansion polymerization with cyclic tin catalysts at 130–160 °C in bulk. By DSC measurements with 10 K min−1 melting temperatures (Tm) in the range of 190–196 °C were found. The WAXS and SAXS measurements evidenced that not a new crystal lattice but a well-ordered morphology and a higher perfection of the crystallites are responsible for the high Tm values and high crystallinities. Under identical reaction conditions SnOct2-catalyzed and alcohol-initiated ROPs do not yield these crystallites. Furthermore, it was found that the standard crystallites are kinetically favored upon rapid crystallization, whereas the high melting form of poly(L-lactide) is thermodynamically more stable. KW - Polylactide KW - MALDI-TOF MS KW - ROPPOC PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507477 DO - https://doi.org/10.1039/c9py01908a VL - 11 IS - 12 SP - 2182 EP - 2193 PB - Royal Society of Chemistry AN - OPUS4-50747 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Meyer, A. A1 - Chatti, S. A1 - Kricheldorf, H. R. T1 - About the transformation of low Tm into high Tm poly(L-lactide)s by annealing under the influence of transesterification catalysts N2 - Cyclic polylactides were prepared in bulk at 170 °C, crystallized at 120 °C and then annealed at temperatures between 130 and 170 C with variation of catalyst, catalyst concentration and annealing time. The transformation of the initially formed low melting (LTm) crystallites, having melting temperatures (Tm) <180 °C into high melting (HTm) crystallites having Tm values > 189 °C was monitored by means of DSC measurements and characterized in selected cases by SAXS measurements. It was confirmed that the formation of HTm crystallites involves a significant growth of the thickness of the lamellar crystallites along with smoothing of their surface. Annealing at 170 °C for 1 d or longer causes thermal degradation with lowering of the molecular weights, a gradual transition of cyclic into linear chains and a moderate decrease of lamellar thickness. An unexpected result revealed by MALDI TOF mass spectrometry is a partial reorganization of the molecular weight distribution driven by a gain of crystallization enthalpy. KW - Polylactide KW - MALDI-TOF MS KW - Crystallization KW - Annealing PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521062 DO - https://doi.org/10.1039/d0ra10012a VL - 11 IS - 5 SP - 2872 EP - 2883 PB - Royal Society of Chemistry AN - OPUS4-52106 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen T1 - Polymerization of L-lactide with SnCl2: A Low Toxic and Eco-friendly Catalyst N2 - Polymerizations of L-lactide catalyzed either by neat SnCl2 or by SnCl2 + difunctional cocatalysts were conducted in bulk at 180, 160 and 140 °C with variation of the Lac/Cat ratio and time. With neat SnCl2 poly(L-lactide) having weight average molecular weights (uncorrected Mw’s) up to 190 000 g mol−1 were obtained mainly consisting of linear chains. Addition of salicylic acid or 1,1-bisphenol yielded a higher fraction of cyclic polylactides but lower molecular weights. Furthermore, SnCl2 was compared with Bu2SnCl2 and various other metal chlorides and the best results were obtained with SnCl2. With ethyl L-lactate as initiator SnCl2-catalyzed ROPs were performed at 120 °C and the lac/initiator ratio was varied. All these experiments were conducted under conditions allowing for comparison with ROPs catalyzed with neat Sn(II)-2-ethyhexanoate. Such a comparison was also performed with ε-caprolactone as monomer. KW - Catalyst KW - Polylactide KW - MALDI-TOF MS KW - Polycondensation PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520517 DO - https://doi.org/10.1007/s10924-020-02042-w SN - 1566-2543 SP - 1 EP - 13 PB - Springer Nature AN - OPUS4-52051 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, H. R. A1 - Weidner, Steffen T1 - High molecular weight poly(l-lactide) via ring-opening polymerization with bismuth subsalicylate-The role of cocatalysts N2 - The catalytic potential of bismuth subsalicylate (BiSub), a commercial drug, for ring-opening polymerization (ROP) of L-lactide was explored by variation of co-catalyst and polymerization time. Various monofunctional phenols or carboxylic acids, aromatic ortho-hydroxy acids and diphenols were examined as potential co-catalysts. 2,2´-Dihydroxybiphenyl proved to be the most successful co-catalyst yielding weight average molecular weights (uncorrected Mw values up to 185 000) after optimization of reaction time and temperature. Prolonged heating (>1-2h) depending on catalyst concentration) caused thermal degradation. In polymerization experiments with various commercial Bi(III) salts a better alternative to BiSub was not found. By means of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry a couple of unusual and unexpected transesterification reactions were discovered. Finally, the effectiveness of several antioxidants and potential catalyst poisons was explored, and triphenylphosphine was found to be an effective catalyst poison. KW - Polylactide KW - MALDI-TOF MS KW - Ring-opening polymerization KW - Bismuth PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519513 DO - https://doi.org/10.1002/app.50394 SN - 0021-8995 VL - 138 IS - 19 SP - 50394 PB - Wiley AN - OPUS4-51951 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -