TY - CONF A1 - Kittner, Maria T1 - Small, everywhere and difficult to detect - Insights into the detection of microplastic particles in environmental samples using thermal extraction desorption-gas chromatography/mass spectrometry N2 - As global demand for polymer products increases, so does the potential amount of leakage into the environment, known as macroplastic (> 1,000 µm) and microplastic particles (MP, 1 - 1,000 µm). To date, the environmental and health consequences are unclear and unpredictable, so robust MP monitoring data are needed to identify the sources, pathways and fate of these particles. Therefore, we developed the thermoanalytical method TED-GC/MS (thermal extraction desorption - gas chromatography/mass spectrometry), which uses polymer-specific thermal decomposition products for the detection of MP in environmental samples. It allows fast identification and the determination of MP mass contents, which is crucial for assessing of their potential effects and thus for legislation and monitoring. For a better understanding of the TED-GC/MS, this presentation will provide the first methodological insights into systematic assessments of TED-GC/MS performance for MP detection in different environmental model matrices. Results of MP determination from real samples will underline the presentation and aspects of practical application will be addressed. To harmonise the method, it is essential to assess different analytical performance parameters (e.g. recovery, signal quality or limit of detection, LOD) to ensure comparability of data. For this purpose, standard addition of different aquatic (e.g. suspended particulate matter, limnic sediment, activated sludge) and terrestrial samples (e.g. agricultural soil) were performed with non-biodegradable standard polymers (polyethylene, PE; polyethylene terephthalate, PET; polypropylene, PP; polymethyl methacrylate, PMMA; polystyrene, PS; styrene-butadiene rubber, SBR) as well as biodegradable polymers (polybutylene adipate terephthalate PBAT; polylactide, PLA) and analysed by TED-GC/MS. These results were then compared with the measurements of the neat polymers without matrix. T2 - SETAC Europe 2021 CY - Online meeting DA - 03.05.2021 KW - Matrix KW - Microplastic particles KW - Mass content KW - TED-GC/MS PY - 2021 AN - OPUS4-52660 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Eisentraut, Paul T1 - Fast quantitative detection of microplastics using TED-GC/MS, an innovative thermoanalytical method N2 - Im Vortrag wird die BAM vorgestellt und die Motivation für Engagement im Feld der Mikroplastikanalysen dargelegt. Die Herausforderungen bei der Analyse werden aufgezeigt und der Umgang mit ihnen. Das Arbeitsprinzip der TED-GC/MS sowie Leistungsparameter werden erläutert sowie das Vorgehen zur Identifikation und Quantifizierung von Polymeren in er Umwelt. An ausgewählten Beispielen werden interessante Ergebnisse präsentiert und die Mikroplastikreferenzmaterialien der BAM vorgestellt. N2 - In the talk, the BAM is introduced and the motivation for our engagement in the field of microplastic analysis is explained. The challenges in the analysis of microplastics are shown and how we deal with them. The working principle of TED-GC/MS and its performance parameters are presented, as well as the procedure for identifying and quantifying polymers in environmental samples. Interesting results are shown using selected examples. Finally, BAM's microplastic reference materials are highlighted. T2 - National Environmental Monitoring Conference CY - Online meeting DA - 02.08.2021 KW - Microplastic KW - TED-GC/MS KW - Environmental analysis PY - 2021 AN - OPUS4-53081 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Altmann, Korinna A1 - Hodoroaba, Vasile-Dan T1 - CUSP inter-laboratory comparisons N2 - In this breakout session first, an introduction is given on the planning and organisation of an inter-laboratory comparison (ILC) under the pre-standardisation plattform VAMAS within the newly formed technical working area TWA 45 Micro and Nano Plastics in the Environment. An update with the ILCs on micro- and nanoplastic performed so far is also given. In the third part, the requirements for a reference materials are presented. The needs from the different H2020 micro- and nanoplastic projects are collected and compiled in an ILC matrix for joint activities as the next steps. T2 - The European Research Cluster to Understand the Health Impact of Micro- and Nanoplastics (CUSP) Launching Event CY - Online meeting DA - 10.06.2021 KW - Microplastic KW - Nanoplastic KW - Inter-laboratory comparison KW - VAMAS KW - Reference material PY - 2021 AN - OPUS4-52808 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Altmann, Korinna T1 - Mikroplastik an der BAM: TED-GC/MS und Referenzmaterialien N2 - Thema ist die Funktionsweise der TED-GC/MS als Methode für die Mikroplastik-Detektion sowie die Herstellung dazugehöriger Referenzmaterialien an der BAM T2 - 25. Kolloquium Massenspektrometrie von Polymeren CY - Online meeting DA - 17.06.2021 KW - Mikroplastik KW - TED-GC/MS KW - Referenzmaterial PY - 2021 AN - OPUS4-52835 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Altmann, Korinna T1 - Results of the Plastic in the environment comparative test N2 - The talk describes the sturcture and the results of the "plastics in the environment" comparative test of 2019. T2 - Symposium "Challenges of microplastic analysis – Bridging state of the art and policy needs” CY - Online meeting DA - 09.09.2021 KW - Microplastic KW - Comparative test KW - ILC PY - 2021 AN - OPUS4-53236 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dittmann, Daniel T1 - Aktivkohle-Charakterisierung als weiterer Schlüssel für das Verständnis der Spurenstoffadsorption in der 4. Reinigungsstufe N2 - Aktivkohle ≠ Aktivkohle, Adäquate Materialcharakterisierung - Voraussetzung für Adsorptionsprognosen und Wasserspezifische Auswahl von Aktivkohleprodukten. Ausblick: Publikationen zu Aktivkohlecharakterisierung und Adsorptionsprognose in Vorbereitung T2 - Wasser 2021 - Jahrestagung der Wasserchemischen Gesellschaft CY - Online meeting DA - 10.05.2021 KW - Aktivkohle KW - Thermogravimetrie KW - Zersetzungsgasanalyse KW - Proximatanalyse PY - 2021 AN - OPUS4-52742 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Linberg, Kevin T1 - Insights into Mechanochemical Reactions using High Pressure XRD and DFT Simulations N2 - The reactivity of organic solids under mechanochemical conditions remains very little understood, though many processes have been found empirically. Importantly, it is not well understood how mechanical treatment induces experimentally observed chemical transformations, and if the elevated pressures arising at the point of impact can play a role in the transformation. To understand this aspect of the mechanochemical reactions, the same compounds need to be explored under high pressure conditions. As a model system, we considered the reaction between the bis(4-chlorophenyl) disulfide and bis(2-nitrophenyl) disulfide. A powder mixture of these two compounds is known to undergo a disulfide exchange reaction under ball milling conditions. Using a combination of X-ray powder diffraction and dispersion-corrected density functional theory calculations, we investigated how this binary solid system behaves at elevated pressures and whether pressure alone can explain its mechanochemical reactivity. T2 - International Scientific Student Conference 2021 CY - Online meeting DA - 12.04.2021 KW - Mechanochemistry KW - High Pressure KW - Density-functional theory PY - 2021 AN - OPUS4-52494 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lakshmipathi, M. A1 - Emmerling, Franziska A1 - Bhattacharya, Biswajit A1 - Ghosh, S. T1 - Structure-mechanical property correlation of a series of 4-(1-Napthylvinyl) pyridine based cocrystals N2 - We obtained three 4-(1-Napthylvinyl) pyridine based cocrystals ( 1–3 ) and studied its structure mechan- ical property correlation which aimed towards various applications for photo switches, mechanical ac- tuators etc. Selection of coformer molecules is important in fine tuning mechanical property outcome of synthesized cocrystals. Amongst three cocrystals, cocrystal 1 is mechanically flexible and its mechani- cal property is attributed to underlying crystal packing features which is in line with existing elastically bendable crystals while other two cocrystals ( 2, 3 ) are brittle in nature. Hirshfeld analysis was carried out to illustrate structure-property correlation particularly in terms of number as well as types of non- covalent interactions in the lattice and further to corroborate the space of the molecules in the lattice. KW - Cocrystals KW - Mechanical properties KW - Halogen bond interaction KW - Structure-mechanical property correlation PY - 2022 DO - https://doi.org/10.1016/j.molstruc.2022.133670 SN - 0022-2860 VL - 1268 SP - 1 EP - 16 PB - Elsevier CY - Amsterdam AN - OPUS4-55547 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Waniek, Tassilo T1 - The practical implementation of MP reference material production according to ISO standards N2 - Micro- and nanoplastic particles became a topic of public concern all over the world e.g. in water, soil, sludge and air. For a profound risk assessment, it is necessary to identify the origins, hotspots, or transport between different media. Therefore, a representative repeatable analysis is required and reference materials (RM) to proof and compare methods. The basis of MNP investigations is a harmonized analysis which includes sampling, sample preparation and detection. In recent years, spectroscopic methods like µRaman and µFTIR for the determination of particle numbers or thermoanalytical methods like Pyrolysis gas chromatography/mass spectrometry (py-GC/MS) and Thermo extraction/ desorption gas chromatography / mass spectrometry (TED-GC/MS) for mass determination have proven to be particularly suitable. The technical committees (TC) of ISO TC 61 “plastics” and TC 147 “water quality" are working on harmonisation processes on international level. For all standardization approaches, it is necessary that the detection methods and analysis processes can be validated. Therefore, BAM develops reference material for microplastic (MP) analysis for several years with focus on the most common polymers PE, PP, PS, PET and PA. MP particles with a close to reality fragment shape are obtained by cryomilling and sieving. For sample preparation purposes with mass detection methods MP particles are pressed into pills with a water-soluble matrix. Thereby losses due to sample preparation e.g. filtration are included in the verification of an analysis. To ensure a constant quality throughout all MP RM batches the homogeneity and stability is controlled according to ISO Guide 35. Next to TED-GC/MS measurements particle size distribution, infrared spectroscopy and differential scanning calorimetry spectra are taken as accompanying parameters. This presentation aims to introduce into the MP RM production process with ensured quality and special focus on pointing out customized setups for particle comminution, separation, and characterization for standardization. T2 - ASTM Syposioum on Microplastic Analytical and Reference Standards - Opportunities to Advance Microplastic Science CY - Seattle, WA, USA DA - 30.06.2022 KW - Microplastic KW - Reference material KW - Cryo milling KW - Polymer PY - 2022 AN - OPUS4-55891 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lukas, M. T1 - Artificial plastic aging as a framework for microplastics ecotoxicity evaluation N2 - Microplastics are widely distributed in aquatic and terrestrial environments, up to now less is known on toxicological impacts under realistic conditions. Research so far has focused mainly on the impacts on organisms by fresh plastic fragments or beats. However, plastic materials found in the environment are mainly a mixture of different polymers and additives and particularly degraded during aging processes. Although especially oxidized degradation products might escape from plastic materials during aging, there is a lack of information on potentially adverse effects on aquatic biota. The latter is of particular interest as oxidized chemicals become more water soluble due to higher polarity and are more bio-available, therefore. The present study focused on plastic leachates of polystyrene (PS) and polylactic acid (PLA), which were derived from alternating stress by hydrolysis and UV radiation. Test specimen of PS, PLA or PS/PLA blends (each 50 %) were alternatingly maintained in water at 45 °C for five days and UV radiated at 45 °C for two days, for in total six weeks. Ecotoxicological effects of potentially generated degradation products of plastic materials in the storage water (mineral water, pH: 7.2) were detected by algae growth inhibition tests with Desmodesmus suspicatus and photosystem II inhibition tests with Raphidocelis subcapitata. Results clearly indicate inhibitory effects on algae growth by contaminants in the storage water of stressed plastic materials with increasing growth inhibition of proceeding hydrolysis and UV stress times. Here, different plastics cause variable responses of algal growth. First chemical analyses indicate dissolved monomers and their oxidation products of plastic materials as possible driver of detected ecotoxicological effects, since detected microplastic particles do not seem to harm algae. The existing data highlight the relevance of plastic aging as a framework for microplastic ecotoxicity evaluation and allow a proof of concept. T2 - 37. DGL-Tagung, Universität Konstanz CY - Konstanz, Germany DA - 19.09.2022 KW - Microplastic KW - Ecotoxicity PY - 2022 AN - OPUS4-55870 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Emmerling, Franziska T1 - Cocrystal polymorphs & Mechanochemistry - Mechanism & Kinetics N2 - Mechanochemistry is an effective, environmentally benign, and facile method for the synthesis of new crystal forms. Different milling parameters are known to affect the mechanisms and rates of product formation: milling frequency, milling time, filling degree of the milling jar, ball diameter and vessel size, degree of milling ball filling, and material of jars. The increasing interest in mechanochemistry is contrasted by a limited mechanistic understanding of mechanochemical reactivity and selectivity. Control over ball milling transformations is needed before the transformative potential of mechanochemical processing can be realized. Different analytical methods and their combinations have been developed for the time-resolved in situ monitoring of mechanochemical transformations, including powder X-ray diffraction, X-ray absorption spectroscopy, NMR, Raman spectroscopy, and thermography. Here we will discuss our recent results investigating the formation of polymorphic cocrystals thereby elucidating the influence of milling parameters (solvent, temperature, time) and reaction sequences on the formation mechanism and kinetics. For the mechanochemical chlorination reaction of hydantoin normalizing the kinetic profiles to the volume of the milling ball showed clearly that milling reaction kinetics are conserved. Here physical kinetics dominate reaction rates in a ball-milling transformation. Attempting to interpret such kinetics in purely chemical terms risk misinterpreting the results. Our results indicate that time-resolved in situ investigations of milling reactions offer a new approach to tune and optimize mechanochemical processes. T2 - 33th European Crrystallography Meeting CY - Versailles, France DA - 23.08.2022 KW - Mechanochemistry KW - Cocrystals KW - Kinetics KW - Polymorphs PY - 2022 AN - OPUS4-55586 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Braun, U. T1 - Detection of plastics in soil N2 - Soil acts as a final sink for pollutants. Microplastics from different sources such as plastic mulching, littering, compost, sewage sludge, sedimentary deposition, and tyre abrasion are expected to be found in soil. However, representative and comprehensive information is missing on the sources, transport, and fate. Therefore, a reliable analysis method for microplastics in soils needs to be developed. The presented work describes the development of a procedure for microplastics analysis in soils. A representative sampling based on the on-site conditions and a sample preparation method was established and comprised of a drying step, the separation of microplastic particles > 1 mm, and a density separation for particles < 1 mm. The detection of the large microplastic particles (> 1 mm) was conducted with Attenuated Total Reflection - Fourier Transform infrared Spectroscopy (ATR-FTIR) , while Thermal Extraction Desorption - Gas Chromatography / Mass Spectrometry (TED-GC/MS) was applied for particles < 1 mm, gaining information on the type of polymer and mass fraction. Based on the established method, 14 environmental soil samples ? with different exposure of microplastics from agriculture, industrial sites, roads, and floods were investigated. Due to the arbitrary microplastic particle distribution among the samples for large microplastics, it was reasoned that the found particles were unrepresentative. In contrast, microplastic particles < 1 mm were discovered in a high mass in soil samples exposed to plastic mulching or fertilization with sewage sludge or compost (0 – 115 mg/kg). On average, microplastic contents detected in soil samples taken from a construction site and an inner-city lake were higher (13 – 238 mg/kg). As expected, microplastic content in soil sampled in proximity to roads was more pronounced in the upper soil layers. In contrast, very remote sampling sites, expectably uncontaminated, did not lead to the detection of microplastic regarding to thermoanalytical detection method. In a proof of concept experiment several in vivo and in vitro ecotoxicological tests were applied to evaluate the effect of microplastics (tyre abrasion, polystyrene containing hexabromocyclododecane) in natural soils. In summary, while no effects of the examined probes could be detected on higher levels of biological organization after exposures to earthworm E. andrei, significant changes in several oxidative stress related biomarkers were observed. T2 - SETAC Europe 2022 CY - Kopenhagen, Denmark DA - 15.05.2022 KW - Microplastic KW - TED-GC/MS KW - Soil PY - 2022 AN - OPUS4-55872 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Emmerling, Franziska T1 - Cocrystal polymorphs & Mechanochemistry - Mechanism & Kinetics N2 - Mechanochemistry is an effective, environmentally benign, and facile method for the synthesis of new crystal forms. Different milling parameters are known to affect the mechanisms and rates of product formation: milling frequency, milling time, filling degree of the milling jar, ball diameter and vessel size, degree of milling ball filling, and material of jars. The increasing interest in mechanochemistry is contrasted by a limited mechanistic understanding of mechanochemical reactivity and selectivity. Control over ball milling transformations is needed before the transformative potential of mechanochemical processing can be realized. Different analytical methods and their combinations have been developed for the time-resolved in situ monitoring of mechanochemical transformations, including powder X-ray diffraction, X-ray absorption spectroscopy, NMR, Raman spectroscopy, and thermography. Here we will discuss our recent results investigating the formation of polymorphic cocrystals thereby elucidating the influence of milling parameters (solvent, temperature, time) and reaction sequences on the formation mechanism and kinetics. For the mechanochemical chlorination reaction of hydantoin normalizing the kinetic profiles to the volume of the milling ball showed clearly that milling reaction kinetics are conserved. Here physical kinetics dominate reaction rates in a ball-milling transformation. Attempting to interpret such kinetics in purely chemical terms risk misinterpreting the results. Our results indicate that time-resolved in situ investigations of milling reactions offer a new approach to tune and optimize mechanochemical processes. T2 - 3rd CEFMC meeting CY - Kashmir, India DA - 31.08.2022 KW - Mechanochemistry KW - Crystal Engeneering PY - 2022 AN - OPUS4-55641 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Altmann, Korinna T1 - Harmonisation efforts of the CUSP projects N2 - The talk is about harmonisation approaches within CUSP. First the five H2020 projects for research on risk assessment regarding microplastics topic were presented. Secondly, harmonisation process were discussed. T2 - VAMAS SC 47 Meeting CY - Turin, Italy DA - 19.10.2022 KW - Microplastics KW - Harmonisation KW - Nanoplastics KW - H2020 KW - Risk assessment PY - 2022 AN - OPUS4-56077 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Braun, U. T1 - Analysis of Microplastics in Soil: Harmonisation and Standardisation - a first approach N2 - The talk is about microplastics in soil. Some results were presented with mainly state of the art according to microplastics in standardization. T2 - International Conference Microplastics in Soils CY - Berlin, Germany DA - 19.10.2022 KW - Microplastics KW - Microplastics standardisation KW - Microplastics in soil PY - 2022 AN - OPUS4-56078 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stroh, Julia A1 - Meng, Birgit A1 - Emmerling, Franziska T1 - Monitoring of sulphate attack on hardened cement paste studied by synchrotron XRD N2 - The complex matter of external sulphate attack on cement-based construction materials is still not completely understood. The concentration of sulphate is a crucial factor for the formation of secondary phases and phase transitions of cement hydrates due to sulphate ingress into the microstructure. The sulphate attack on building materials for high and low sulphate concentrations was monitored by laboratory experiments. Hardened cement paste consisting of ordinary Portland cement (CEM I) were exposed to aqueous solutions of sodium sulphate for 18 months. Three sample compositions were used for this research, including different supplementary cementitious materials (SCM). The phase composition was determined for different time spans by high resolution synchrotron X-ray diffraction. Cross sections of exposed cement prisms were investigated as a representation of the microstructural profile. Based on the data, a temporal and spatial determination of the stages of the sulphate attack and the deterioration course was possible. Cement matrices blended with slag showed the highest resistance against sulphate attack. KW - Cement paste KW - Sulphate attack KW - Mineral additions KW - Concentration KW - Monitoring PY - 2015 DO - https://doi.org/10.1016/j.solidstatesciences.2015.08.006 SN - 1293-2558 SN - 1873-3085 VL - 48 SP - 278 EP - 285 PB - Elsevier Masson SAS CY - Amsterdam AN - OPUS4-34281 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schlegel, M.C. A1 - Stroh, Julia A1 - Malaga, K. A1 - Meng, Birgit A1 - Panne, Ulrich A1 - Emmerling, Franziska T1 - Pathway of a damaging mechanism - Analyzing chloride attack by synchrotron based X-ray diffraction N2 - Typically, the changes of the phase compositions due to the chemical attack are studied in-situ only by chemical analysis or microscopy. In this study, the chloride transport and binding in the cement matrix in different cementitious materials was analyzed by synchrotron based X-ray diffraction (SyXRD) and energy dispersive X-ray spectroscopy (EDX). Sample materials consisting of cement paste were embedded in high concentrated sodium chloride solution over different time spans. Afterwards, the phase and chemical compositions were determined. The high spatial resolution and the information about the chloride distribution offer a detailed view of chloride binding in the cement matrix and allow the conclusions about the degradation mechanisms. The results are discussed related to the influence of different supplementary cementitious materials on the damaging mechanism. KW - Portland cement KW - In-situ KW - X-Ray diffraction KW - EDX KW - Durability KW - Chloride attack PY - 2015 DO - https://doi.org/10.1016/j.solidstatesciences.2015.03.021 SN - 1293-2558 SN - 1873-3085 VL - 44 SP - 45 EP - 54 PB - Elsevier Masson SAS CY - Amsterdam AN - OPUS4-33171 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mönch, Bettina A1 - Kraus, Werner A1 - Köppen, Robert A1 - Emmerling, Franziska T1 - The different conformations and crystal structures of dihydroergocristine N2 - The identification of different forms of dihydroergocristine (DHEC) was carried out by crystallization from different organic solvents. DHEC was identified as potential template for molecularly imprinted polymers (MIPs) for the epimeric specific analysis of ergot alkaloids (EAs) in food. DHEC was crystallized from different solvents in order to mimic the typical MIP synthesis conditions. Four new solvatomorphs of DHEC were obtained. All solvatomorphs contain a water molecule in the crystal structure, whereas three compounds contain an additional solvent molecule. Based on the conformation of DHEC a comparison with typical EA molecules was possible. The analysis showed that DHEC is a suitable template for MIPs for EAs. PY - 2016 DO - https://doi.org/10.1016/j.molstruc.2015.10.008 SN - 0022-2860 SN - 1872-8014 SN - 0377-046X VL - 1105 SP - 389 EP - 395 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-35009 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fischer, Franziska A1 - Heidrich, Adrian A1 - Greiser, Sebastian A1 - Benemann, Sigrid A1 - Rademann, K. A1 - Emmerling, Franziska T1 - Polymorphism of mechanochemically synthesized cocrystals: a case study N2 - The liquid-assisted grinding cocrystallisation of theophylline with benzamide leading to polymorphic compounds was investigated. A solvent screening with seventeen different solvents was performed. The dipole moment of the solvent used in the synthesis determines the structure of the polymorphic product. A detailed investigation leads to the determination of the kinetically and thermodynamically favored product. In situ observations of the formation pathway during the grinding process of both polymorphs show that the thermodynamically favored cocrystal is formed in a two-step mechanism with the kinetic cocrystal as intermediate. KW - cocrystal KW - mechanochemistry KW - theophylline KW - benzamide KW - milling KW - polymorphism PY - 2016 DO - https://doi.org/10.1021/acs.cgd.5b01776 SN - 1528-7483 SN - 1528-7505 VL - 16 IS - 3 SP - 1701 EP - 1707 AN - OPUS4-35618 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stroh, Julia A1 - Schlegel, Moritz-Caspar A1 - Schmidt, Wolfram A1 - Nguyen, Thi Yen A1 - Meng, Birgit A1 - Emmerling, Franziska T1 - Time-resolved in situ investigation of Portland cement hydration influenced by chemical admixtures N2 - Numerous admixtures are used in the building practice to customize the properties of the cement paste during application. The influences of admixtures on the course of cement hydration and formation of hydrate phases have to be considered. Polycarboxylate ether (PCE) based polymeric superplasticizers (SPs) are known to retard the setting of the cement paste. The extent of the retardation differs depending on the molecular structure of the SP. Additionally, the presence of a stabilizing agent (SA) in the cement paste has a retarding side effect on the setting. The initial cement hydration processes and the detailed mechanisms of the retardation influenced by PCEs, as well as their interactions with particular SAs, are insufficiently understood. Up to now, only the results of phenomenological studies were taken into account to describe this retardation process. A detailed structure analysis monitoring the change of the phase composition during the hydration was never applied. Both SP and SA affect the adsorption of the sulphate ions on the clinker particles, causing changes in the formation of ettringite during the initial hydration, and are therefore a crucial part of the setting process itself. Here, the initial hydration of cement influenced by the interaction of SP and SA was monitored in situ by synchrotron X-ray diffraction. The high time resolution of the measurements allowed a continuous detection of the hydrates formed. The hydration was followed from the starting point of water addition and for couple of hours afterwards. The hydration of the levitated cement pellets containing starch as SA was initialized by adding aqueous solutions of different commercial SPs. Changes in the ettringite formation were detected in comparison to the reference hydration of pure cement. KW - Synchrotron KW - Portland cement Initial hydration KW - Superplasticizer KW - Stabilizer KW - XRD PY - 2016 DO - https://doi.org/http://dx.doi.org/10.1016/j.conbuildmat.2015.12.097 IS - 106 SP - 18 EP - 26 PB - Elsevier AN - OPUS4-35467 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fischer, Franziska T1 - Survival of the fittest - Competetive cocrystal reactions in the ball mill N2 - Mechanochemistry is increasingly used for synthesizing various materials including cocrystals and metal organic compounds. Although this synthesis approach offers a fast and pure synthesis in high yields there is a lack in understanding the mechanisms of milling reactions. The driving forces triggering the formation of cocrystals under milling conditions were investigated using a set of multi-component competitive milling reactions. In these reactions, different active pharmaceutical ingredients were ground together with a further compound acting as coformer. The study was based on new cocrystals including the coformer anthranilic acid. The results of the competitive milling reactions indicate that the formation of cocrystals driven by intermolecular recognition are influenced and inhibited by kinetic aspects including the formation of intermediates and the stability of the reactants. T2 - Berliner Chemie Symposium CY - Berlin, Germany DA - 12.04.2016 KW - milling KW - cocrystal KW - mechanochemistry PY - 2016 AN - OPUS4-35862 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Oliveira Guilherme Buzanich, Ana A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Riesemeier, Heinrich A1 - Emmerling, Franziska ED - de Oliveira Guilherme Buzanich, Ana T1 - Time- and spatial-resolved X-ray absorption fine structure (XAFS) spectroscopy in a single-shot: new analytical possibilities for in situ material characterization N2 - A new concept that comprises both time- and lateral-resolved X-ray absorption fine-structure information simultaneously in a single shot is presented. This uncomplicated set-up was tested at the BAMline at BESSY-II (Berlin, Germany). The primary broadband beam was generated by a double multilayer monochromator. The transmitted beam through the sample is diffracted by a convexly bent Si (111) crystal, producing a divergent beam. This, in turn, is collected by either an energy-sensitive area detector, the so-called color X-ray camera, or by an area-sensitive detector based on a CCD camera, in θ-2θ geometry. The first tests were performed with thin metal foils and some iron oxide mixtures. A time resolution of lower than 1 s together with a spatial resolution in one dimension of at least 50 µm is achieved. KW - Single-shot XAFS KW - Time resolution KW - Spatial resolution KW - Divergent XAFS PY - 2016 DO - https://doi.org/10.1107/S1600577516003969 SN - 1600-5775 VL - 23 SP - 769 EP - 776 PB - International Union of Crystallography AN - OPUS4-38370 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -