Open Access

This study examines two comprehensive approaches to reducing the amount of antimony trioxide (ATO) in brominated flame retardant (tris(2,4,6‐tribromophenoxy)‐s‐triazine bromine) (Br) in acrylonitrile–butadiene–styrene (ABS). One approach systematically substitutes Br/ATO with magnesium hydroxide (MH), while the other substitutes ATO with calcium borate, zinc borate, zinc oxide, zinc sulfide, and zinc stannate. We investigated the pyrolysis (thermogravimetry), flammability (limiting oxygen index and UL 94 tests), smoldering (smoke density chamber), and fire behavior (cone calorimeter). The study reveals that the synergism between Br and ATO is essential and sensitive to any changes. None of the additives fully replaced the Br/ATO mixture or ATO alone while maintaining the same level of flame retardancy. Replacing the Br/ATO mixture with MH reduces smoke emission during burning but increases flammability in the ignition scenario. Zinc and calcium salts considerably lower the peak of heat release rate due to the enhanced formation of a protective char layer. The residual protective layer hinders mass and heat transfer, and prolonged residence time of the decomposition products in the pyrolytic zone results in smoke reduction. This systematic investigation illustrates the challenges of replacing Br/ATO or ATO in ABS, but it also emphasizes the relevant benefits and remarkable potential of partial replacement.

Reference materials are indispensable for obtaining reliable measurement results. Incorrect values cost time and money, because at best they lead to measurements having to be re-peated and at worst they can cause wrong decisions with far-reaching consequences. To achieve a meaningful comparison between results obtained by different laboratories using the Friction After Polishing (FAP) test method, it is therefore essential to use elastomer materials with similar properties. The Federal Institute for Materials Research and Testing (BAM) has been working on the de-velopment of reference materials for more than 100 years. A comprehensive quality manage-ment system ensures that the production of such materials meets the requirements of DIN EN ISO 17034. BAM currently offers over 400 reference materials for various applications. This also includes more than 20 elastomer reference materials. At the moment, a team from the elastomer group of BAM division 7.5 is working in coopera-tion with the Federal Highway Research Institute (BASt) on the development of rubber sliding blocks and polishing rollers that can serve as reference materials for FAP devices in the fu-ture. This presentation describes the hurdles that have already been overcome and outlines the next steps.

Analysis of nanomaterial (NM) surface chemistry is essential for understanding and controlling NM properties relevant for NM functionality, stability, and safety. In this work, we present a multimethod study of the quantification of the frequently used, biocompatible surface ligand citrate for lanthanide-based upconversion nanoparticles (UCNPs) and iron oxide nanoparticles (IONPs). Methods applied that address different yet correlated measurands with varying chemo-selectivity and rely on different sample preparation workflows include chemo-selective reversed-phase high-performance liquid chromatography (RP-HPLC) with photometric detection measuring liquid samples and dissolved NMs as well as non-selective thermogravimetric analysis (TGA) and chemo-selective pyrolysis-gas chromatography-mass spectrometry (PyGC-MS) analyzing dried NMs. Thereby, we demonstrate the applicability of the RP-HPLC method, recently developed for citrate quantification on IONPs, for UCNPs as another application-relevant NM class. In addition, the feasibility of PyGC-MS, emerging for material characterization at the trace level due to the consumption of very small sample amounts and minimum sample preparation, for NM ligand quantification is assessed. This method, which has not been applied before for NM surface analysis, indirectly quantifies citrate via the amount of acetone formed during citrate decomposition. For UCNPs, PyGC-MS measurements led to a good agreement with the TGA and RP-HPLC results within the respective measurement uncertainties. However, quantifying citrate on IONPs with PyGC-MS resulted in an overestimation of citrate, which is tentatively ascribed to IONP catalytic activity. Overall, our method cross-comparison underlines the importance of multimethod characterization schemes to assure a reliable and precise ligand quantification and to identify method- and NM-specific effects.

Flame retardant polyurethane (PU) foams and thermoplastic PU are proposed for insulation, seat cushioning, or cable jackets. PU consists of alternating segments that tailor the material properties while also determining the pyrolysis and fire behavior. Most PU materials are highly flammable and tend to form pool fires or burning drops; although rigid and flexible PU foams are two different stories, their low thermal inertia results in short ignition times and intensive flame spread. The important PU markets are dying for developing novel flame-retardant PU materials that outperform the existing ones. This work delivers detailed insight into the complex burning behavior of PU-materials. The comprehensive understanding of the physical and chemical processes and their complex interplay, respectively, is presented as the foundation of customized development of future PU materials.

Für ein Prüflaboratorium ist die richtige Anwendung von Prüfnormen von grundlegender Bedeutung. Um die Kompetenz des Labors zu belegen, sind Ringversuche ein wichtiges Mittel. In dem Vortrag wurde gezeigt, wie ein Prüflaboratorium die Teilnahme an Ringversuchen zu diesem Zweck nutzen kann. Welche aktuellen Anforderungen gibt es bei einer Akkreditierung als Prüflaboratorium? Wie kann die Beteiligung an einem Ringversuch nach ISO 4649 genutzt werden, um die Unsicherheit der Ergebnisse des Verfahrens für das Prüflaboratorium zu ermitteln?