TY - JOUR A1 - Bui, Minh A1 - Heinekamp, Christian A1 - Fuhry, Emil A1 - Weidner, Steffen A1 - Radnik, Jörg A1 - Ahrens, Mike A1 - Scheurell, Kerstin A1 - Balasubramanian, Kannan A1 - Emmerling, Franziska A1 - Braun, Thomas T1 - Lewis-acid induced mechanochemical degradation of polyvinylidene fluoride: transformation into valuable products N2 - Polyvinylidene fluoride (–[CH2CF2]n–, PVDF) waste poses significant environmental challenges due to its recalcitrant nature and widespread use. This study addresses the end-of-life management of PVDF by introducing a novel, sustainable mechanochemical approach for its valorisation. We investigated the degradation of PVDF into value-added materials using ball milling with anhydrous AlCl3 to achieve a quantitative mineralisation producing AlF3 and halide-functionalised graphite, along with gaseous products (HCl and CH4). Mechanistic key steps involve Lewis-acid catalysed C–F bond activation, dehydrofluorination and aromatisation. This approach provides an effective solution for PVDF waste management while offering a promising route for the production of high-value materials from polymer waste streams. Our findings contribute to sustainable practices in polymer recycling and resource recovery, respond to pressing environmental concerns associated with fluoropolymer disposal, and demonstrate the potential to convert polymer wastes into useful products. KW - Mechanochemistry KW - Polyvinylidenfluoride KW - Degradation KW - Ball mill PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649015 DO - https://doi.org/10.1039/d5sc05783c SN - 2041-6520 VL - 16 IS - 40 SP - 18903 EP - 18910 PB - Royal Society of Chemistry (RSC) AN - OPUS4-64901 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bosc-Bierne, Gaby A1 - Weller, Michael G. T1 - Investigation of impurities in peptide pools T1 - Untersuchung von Verunreinigungen in Peptidpools N2 - Peptide pools are important research tools in different biomedical fields. They consist of a complex mixture of defined peptides, which places high demands on the production and quality control of these products. Previously it has been shown that the combination of UHPLC with high-resolution mass-spectrometry (HRMS) is a fast and powerful method to confirm the relative concentration and the structural identity of all peptides expected to be in the pool. In this work, the additional information contained in the UV chromatograms and mass spectra is used to search for impurities due to synthesis by-products and degradation during storage and transportation and to identify possible analytical artifacts. It was shown that most impurities are only present in trace amounts and can be considered uncritical for most applications. The most frequent and perhaps unexpected impurities were homo- and heterodimers caused by the free cysteines contained in these peptide pools. Furthermore, pyroglutamate and aspartimide formation, deamidation, methionine oxidation, and amino acid deletions could be found. This list is not intended to be comprehensive, but rather a brief guide to quickly identify impurities and, in the long term, to suggest possible changes in the composition of the peptide pools to avoid such impurities by design or by special precautions. N2 - Peptidpools sind wichtige Forschungsinstrumente in verschiedenen biomedizinischen Bereichen. Sie bestehen aus einer komplexen Mischung definierter Peptide, was hohe Anforderungen an die Herstellung und Qualitätskontrolle dieser Produkte stellt. In der Vergangenheit wurde gezeigt, dass die Kombination von UHPLC mit hochauflösender Massenspektrometrie (HRMS) eine schnelle und leistungsfähige Methode zur Bestätigung der relativen Konzentration und der strukturellen Identität aller Peptide ist, die in dem Pool erwartet werden. In dieser Arbeit werden die zusätzlichen Informationen, die in den UV-Chromatogrammen und Massenspektren enthalten sind, genutzt, um nach Verunreinigungen zu suchen, die auf Nebenprodukte der Synthese und den Abbau während der Lagerung und des Transports zurückzuführen sind, und um mögliche analytische Artefakte zu identifizieren. Es hat sich gezeigt, dass die meisten Verunreinigungen nur in Spuren vorhanden sind und für die meisten Anwendungen als unkritisch angesehen werden können. Die häufigsten und vielleicht unerwartetsten Verunreinigungen waren Homo- und Heterodimere, die durch die in diesen Peptidpools enthaltenen freien Cysteine verursacht werden. Außerdem wurden Pyroglutamat- und Aspartimidbildung, Deamidierung, Methioninoxidation und Aminosäuredeletionen festgestellt. Diese Liste erhebt keinen Anspruch auf Vollständigkeit, sondern ist eher ein kurzer Leitfaden, um Verunreinigungen schnell zu identifizieren und langfristig mögliche Änderungen in der Zusammensetzung der Peptidpools vorzuschlagen, um solche Verunreinigungen durch Design oder besondere Vorsichtsmaßnahmen zu vermeiden. KW - Synthetic peptides KW - Degradation KW - Synthetic artifacts KW - Peptide losses KW - Stability of peptides KW - Disulfide dimers KW - Cysteine dimers KW - Isomers KW - Cysteine alkylation PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626987 DO - https://doi.org/10.3390/separations12020036 SN - 2297-8739 VL - 12 IS - 2 SP - 1 EP - 18 PB - MDPI AG CY - Basel AN - OPUS4-62698 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Agudo Jácome, Leonardo T1 - The Al4-xZr5(Ox-y) Trojan horse in the AlMo0.5NbTiTa0.5Zr refractory high entropy superalloy N2 - Unlike conventional alloys, which typically consist of one main element, high-entropy alloys (HEAs) contain five or more principal elements, which broaden chemical complexity and with it a realm of synergistic mechanisms. The AlMo0.5NbTa0.5TiZr HEA initiated a subclass of Al-containing refractory (r)HEAs that has recently drawn attention [2]. The alloy has a superalloy-resembling B2/bcc nanostructure, which inspired its name refractory high entropy superalloy (RSA). With high-temperature (HT) compressive strengths beyond conventional Ni-based superalloys, this nanostructure could be used for improved HT structural applications. However, in the application-relevant HT regime the Al-Zr-rich B2 phase decomposes to form a hexagonal Al-Zr-based intermetallic (Al4-xZr5; x: 0..1) [3,4]. This work explores the fascinating yet fatal micromechanisms associated to this phase transformation, in the context of creep, annealing and oxidation experiments performed between 800 and 1200 °C. The material was produced by arc-melting and heat treatment in argon, which lead to grain boundaries decorated with up to 7%. Interrupted constant-load creep tests were performed under vacuum (at 10-4 Pa), at 900–1100 °C with external tensile stresses of 30–120 MPa. Oxidation experiments were separately conducted for 24 hours at 800 and 1000 °C in both dry (21% O2 + 79% N2) and humid (8% O2 + 74% N2 + 18% H2O) air. After the experiments, the samples were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy to reveal degradation mechanisms. Crystallographic texture, orientation relationships and stabilization of an oxygen-containing iso structure (Al4-xZr5(Ox-y); y: 0..x) of the Al-Zr-rich intermetallic are found and discussed. T2 - BCC Superalloy Network Opening Workshop CY - Reutte, Austria DA - 08.02.2024 KW - High entropy alloy KW - Superalloy KW - Degradation KW - Electron microscopy KW - Microstructure PY - 2024 AN - OPUS4-59833 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - John, Sebastian A1 - Duffner, Eric A1 - Mair, Georg W. T1 - Degradation and damage analysis of composite pressure vessels via experimental modal analysis N2 - For mobile gas storage systems, the application of type IV pressure vessels is state of the art. Type IV tanks consist of an inner polymer liner fully wrapped with fibre-reinforced plastic (FRP). Because of the complex fabric of the FRP as well as a difficulty estimable interaction behaviour between the single components under load, there are still no satisfying non-destructive testing methods to assess the current state of failure nor to estimate the level of degradation accurately and economically. At BAM division 3.5, analysing the ageing process of mobile composite pressure vessels is a major task to ensure safe usage over the whole lifetime. In this context, key aspects of our ongoing research activities are the invention of new test procedures and the development of accurate lifetime prediction models. In order to determine the level of degradation or damage, one meaningful non-destructive approach is to analyse the structural dynamic behaviour via an experimental modal analysis (EMA). Over the last few years, different types and sizes of composite pressure vessels have been tested in several research projects. The presented paper gives an insight into how to extract and interpret modal parameters and how to fit them to the results of residual strength tests. T2 - NOVEM Conference 2023 CY - Auckland, New Zealand DA - 09.01.2023 KW - Composite material KW - Pressure vessel KW - Degradation KW - Modal analysis PY - 2023 SP - 57-1 EP - 57-6 AN - OPUS4-58062 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - John, Sebastian A1 - Duffner, Eric T1 - Degradation and damage analysis of composite pressure vessels via experimental modal analysis N2 - For mobile gas storage systems, the application of type IV pressure vessels is state of the art. Type IV tanks consist of an inner polymer liner fully wrapped with fibre-reinforced plastic (FRP). Because of the complex fabric of the FRP as well as a difficulty estimable interaction behaviour between the single components under load, there are still no satisfying non-destructive testing methods to assess the current state of failure nor to estimate the level of degradation accurately and economically. At BAM division 3.5, analysing the ageing process of mobile composite pressure vessels is a major task to ensure safe usage over the whole lifetime. In this context, key aspects of our ongoing research activities are the invention of new test procedures and the development of accurate lifetime prediction models. In order to determine the level of degradation or damage, one meaningful non-destructive approach is to analyse the structural dynamic behaviour via an experimental modal analysis (EMA). Over the last few years, different types and sizes of composite pressure vessels have been tested in several research projects. The presented paper gives an insight into how to extract and interpret modal parameters and how to fit them to the results of residual strength tests. T2 - NOVEM 2023 CY - Auckland, New Zealand DA - 09.01.2023 KW - Pressure vessel KW - Composite KW - Modal analysis KW - Degradation PY - 2023 AN - OPUS4-58063 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wiesner, Yosri T1 - Erfassung von Degradationsprodukten und Additiven sowie temperaturspezifische Pyrolyseprodukte mittels TED-GC/MS N2 - Im der Präsentation werden, neben der Möglichkeit der Mikroplastikquantifizierung, auf weitere Anwendungsfelder der Methode TED-GC/MS eigegangen. Dies beinhaltet die Erfassung von Degradationsprodukten UV/O2 geschädigter Polymere und die Detektion von Additiven. Die Optimierung der Methode betreffend Messzeit und materialspezifischer Messanforderung sind ebenfalls Gegenstand. T2 - Kolloquium Massenspektrometrie von Polymeren CY - Berlin, Germany DA - 09.05.2023 KW - TED-GC/MS KW - Polymere KW - Degradation KW - Additive PY - 2023 AN - OPUS4-57480 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meurer, Maren T1 - Is olypropylene relevant for microplastic analytics? N2 - Nowadays, in every terrestrial and aquatic ecosystem, even in the remotest areas, small residues of plastics, the so called microplastic (MP) can be found. MPs are particles with a size of 1-1000 µm (ISO/TR 21960:2020), mainly containing synthetic polymers like polyethylene (PE), polypropylene (PP), polystyrene (PS) or polyethylene terephthalate (PET). Even styrene-butadiene rubber (SBR) as an indication for tire wear is included due to similar particle formation. To understand the MPs consequences to the environment, it is of high priority to capture its extent of contamination. It is surprising that in the analysis of polymer masses in environmental samples, PE, PS and SBR are often detected, but only small amounts of PP, although this is the second most commonly produced standard plastic and many MP particles originate from carelessly disposed packaging materials. This presentation provides hypotheses about the reasons of rare PP identification and mass quantification in environmental samples. Different investigations of pristine PP and representative environmental samples, including the pre-treatment by Accelerated Solvent Extraction (ASE) or with density separation followed by the thermal extraction / desorption gas chromatography-mass spectrometry (TED-GC/MS) are presented. The results are discussed according to the material properties and a possible degradation mechanism under different weathering conditions which indicate less stability under relevant storage conditions. T2 - Society of Environmental Toxicology and Chemistry CY - Dublin, Ireland DA - 30.04.2023 KW - Sample preparation KW - Polypropylene KW - Microplastic KW - Degradation PY - 2023 AN - OPUS4-57474 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weber, Simone T1 - Influence of the pH Value to the Degradation of Ester-Based Thermoplastic Polyurethanes N2 - Microplastics are solid polymeric particles with a size of 1-1000 μm (ISO/TR21960:2020), which can be emitted from mismanaged waste into the environment, where microplastic is now ubiquitous. What happens to the microplastics after ending up in the environment, which risks entail and what effects it has are not sufficiently clarified up to now. The most certain issue is that the plastic particles in the environment are exposed to natural ageing, are fragmenting and degrading, such that the potential risk to ecosystems and humans is increasing due to the formation of smaller and smaller particles, potentially even including nanoplastics, if these are ingested before their further degradation. Therefore, and in view of a possible registration of polymers under REACH in the future, it is necessary to investigate the degradation of thermoplastic polyurethanes (TPU) regarding hydrolysis stability to evaluate possible risks and effects to the environment. In the present studies, one thermoplastic polyurethane – with and without hydrolysis stabilizer – is exposed to different pH buffers at 50°C for 14 days to investigate hydrolysis depending to different pH values (acid, alkali and neutral) based on OECD guideline TG111. The hydrolysis behavior of the TPUs is characterized by surface sensitive techniques and on bulk properties. First degradation effects can be detected by SEC. Hydrolysis, especially under acidic and basic conditions, leads to chain scissions to lower molecular masses. Furthermore, the degradation products which indicate the structure of the bulk material were detected by thermo-analytical methods like TGA-FTIR for the small degradation products and the thermo extraction/desorption-gaschromatography/mass spectrometry (TED-GC/MS) for bigger degradation products. Acidic and basic hydrolysis shows the same degradation behavior which is caused by a preferred scission of the ester and urethane functionalities. Surface-sensitive techniques such as XPS demonstrate less carboxylic acid formation at acidic than at alkaline pH value in the TPU without stabilator, where as the TPU with stabilator ages to the same extent in both pH ranges. Altogether, the hydrolysis of TPUs – independently of added stabilizer or not – in acid and alkali environment is accelerated compared to the neutral hydrolysis. T2 - SETAC CY - Dubin, Ireland DA - 30.04.2023 KW - Degradation KW - Thermoplastic Polyurethane KW - Microplastic KW - Polymer Hydrolysis KW - Polymer 3R KW - REACH PY - 2023 AN - OPUS4-58906 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Richter, Tim A1 - Rhode, Michael T1 - Hydrogen embrittlement and mechanical properties of 9 % Cr P92 steel and P91 weld metal N2 - Martensitic 9 %-Cr steels like P91 and P92 can show an increased susceptibility to delayed hydrogen assisted cracking. The focus of this study was the microstructure and heat treatment effect on the mechanical properties of P92 base material and P91 multi-layer weld metal in both as-welded and post weld heat treated (PWHT) condition. Tensile tests with hydrogen free reference samples and electrochemically hydrogen charged samples were carried out, the mechanical properties were assessed and supported by dedicated fractographic analysis. In addition, hydrogen and microstructure dependent fracture criteria were calculated. All investigated microstructures showed a hydrogen influenced degradation of the mechanical properties compared to the hydrogen free reference samples. In that connection, the as welded martensitic P91 weld metal had the highest degree of degradation in presence of hydrogen. The P91 PWHT weld metal and the P92 base material had comparable properties. From that point of view, a significantly increased risk for hydrogen assisted cold cracking during welding fabrication of P91 weld joints must be considered before any heat treatment is conducted. T2 - IIW Annual Assembly, Meeting of Commission IX-C CY - Tokyo, Japan DA - 21.07.2022 KW - Creep-resistant steel KW - Mechanical properties KW - Hydrogen assisted cracking KW - Weld joint KW - Degradation PY - 2022 AN - OPUS4-55462 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wachtendorf, Volker T1 - Maßgeschneiderte künstliche Bewitterungstests zur Untersuchung der alterungsbedingten Freisetzung von Produkten in die Umwelt N2 - Genormte künstliche Bewitterungstests sind häufig nicht spezifisch für die Anwendungssituation oder das Material. Das macht die Entwicklung spezifischer Tests erforderlich. Für deren Entwicklung müssen Maximalparameter der Anwendungssituation bekannt sein, womit dann der künstliche Test formuliert wird und dessen Bedingungen werden dann solange optimiert, bis die Korrelation der Effekte von natürlichem und künstlichem Test ausreichend ist. Für Untersuchungen der Freisetzung kann der verbleibende Rest in der Probe und/oder die freigesetzte Menge in Luft, Boden, Wasser bestimmt werden. Im ersten Beispiel der Witterungswirkung wurde die Freisetzung von Kohlenstoff-Nanoröhrchen (CNT) aus Polymer-Kompositen untersucht (unter Verwendung von empfindlich-nachweisbarer radioaktiver 14C-Markierung für einzelne CNT-Partikel), in einem zweiten die Freisetzung von anorganischen und organischen Bestandteilen aus elastomeren Bestandteilen von Sportböden (Bahnen und Kunstrasen) in Wasser. T2 - SKZ-Tagung: Bewitterung van Kunststoffen CY - Würzburg, Germany DA - 06.07.2022 KW - Künstliche Bewitterung KW - UV KW - Degradation KW - Freisetzung KW - CNT KW - Carbo-Nanotubes KW - Composite KW - Nano-Partikel KW - 14C-Markierung KW - Sportböden KW - Kunstrasen KW - Grundwasser PY - 2022 AN - OPUS4-55219 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -