TY - JOUR A1 - Kaltzakorta, O. A1 - Wäsche, Rolf A1 - Hartelt, Manfred A1 - Aginagalde, A. A1 - Tato, W. T1 - Influence of polymer filler on tribological properties of thermoplastic polyurethane under oscillating sliding conditions against cast iron N2 - The tribological behaviour of unfilled thermoplastic polyurethane (TPU) and a polymer sphere filled (TPUG) thermoplastic polyurethane have been studied under oscillating sliding condition against cast iron as a counterpart. In the case of unfilled TPU, the wear mechanisms are dominated by particle detachment and roll formation. In principle, TPUG also showed a similar wear mechanism as that of unfilled TPU; in addition, particle pull-out and delamination are also observed. Wear volume of TPUG was significantly higher than that for the unfilled TPU and this is attributed to the different material removal processes taking place in the material during sliding. The polymer spheres as a filler material deteriorated the wear resistance of TPU because of improper adhesion and bonding of filler in the TPU matrix and therefore it contributed to more wear. In case of TPU the friction behaviour was strongly dependant on the temperature and surface roughness of the counter body. The results showed that below the glass transition temperature higher friction values are observed with higher counter body surface roughness. However, above the glass transition temperature, higher friction values are observed with a smoother surface roughness of the counter body. In case of TPUG, the friction behaviour was not significantly dependent on surface roughness of the counter body. KW - Dry sliding KW - Polymers KW - Cast iron KW - Temperature PY - 2012 DO - https://doi.org/10.1007/s11249-012-0017-6 SN - 1023-8883 SN - 1573-2711 VL - 48 IS - 2 SP - 209 EP - 216 PB - Springer Science Business Media B.V. CY - Dordrecht AN - OPUS4-27272 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wachtendorf, Volker T1 - „Test Tailoring“ eines künstlichen Bewitterungstests am Beispiel der Entwicklung des „Acid Dew and Fog“ Testes N2 - Häufig ist es wünschenswert, für neue Materialien oder Anwendungen künstliche Bewitterungsverfahren zu benutzen, die auf die spezifischen Anforderungen besser zugeschnitten sind, als es bei bestehenden standardisierten Verfahren der Fall ist. Nachdem man die spezifischen Parameter der Beanspruchung unter Anwendungsbedingungen und die spezifische Empfindlichkeit des Materials erfasst hat, beginnt ein Prozess, der als „Test Tailoring“ häufig abstrakt verwendet, auf den aber nur selten näher eingegangen wird. Genau dieser Prozess soll hier am Beispiel der Entwicklung eines künstlichen Bewitterungstests unter saurer Beaufschlagung, dem in der BAM entwickelten Acid Dew and Fog Test, beispielhaft erläutert werden. T2 - 47. Jahrestagung der Gesellschaft für Umweltsimulation (GUS) 2018 CY - Pfinztal (Berghausen), Germany DA - 21.03.2018 KW - Test Tailoring KW - Bewitterung KW - Acid Dew and Fog KW - Umweltsimulation PY - 2018 AN - OPUS4-46542 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karrasch, Andrea A1 - Wawrzyn, Eliza A1 - Schartel, Bernhard A1 - Jäger, Christian T1 - Solid-state NMR on thermal and fire residues of bisphenol A polycarbonate/silicone acrylate rubber/bisphenol A bis(diphenyl-phosphate)/(PC(SiR/BDP) and PC/SiR/BDP/zinc borate (PC/SiR/BDP/ZnB) - Part 1: PC charring and the impact of BDP and ZnB N2 - Structural changes in the condensed phase of bisphenol A polycarbonate (containing 0.45 wt% poly (tetrafluoroethylene))/silicone acrylate rubber/bisphenol A bis(diphenyl-phosphate) (PC/SiR/BDP) and PC/SiR/BDP/zinc borate (PC/SiR/BDP/ZnB) during thermal treatment in nitrogen atmosphere and in fire residues were investigated by solid-state NMR. H-1, B-11, C-13 and P-31 NMR experiments using direct excitation with a single pulse and H-1-P-31 cross-polarization (CP) were carried out including 31P(1 H) and C-13{P-31}double-resonance techniques (REDOR: Rotational Echo Double Resonance) on a series of heat-treated samples (580 K-850 K). Because many amorphous phases occur in the solid residues, and solid-state NMR spectroscopy addresses the most important sites carbon, phosphorus and boron, this paper is the key analytical approach for understanding the pyrolysis and flame retarding phenomenon in the condensed phase of PC/SiR/BDP and PC/SiR/BDP/ZnB. For the system PC/SiR/BDP it is shown that (i) at temperatures around 750-770 K (main decomposition step) carbonaceous charring of PC occurs and arylphosphate structures are still present, reacted in part with the decomposing PC; (ii) for higher temperatures from 770 K the phosphorus remaining in the solid phase increasingly converts to amorphous phosphonates and inorganic orthophosphates with a minor amount of crystalline orthophosphates; and (iii) H-1-P-31{H-1} CP REDOR and H-1-C-13{P-31} CP REDOR NMR experiments suggest that the phosphates and phosphonates are bound via oxygen to aromatic carbons, indicating the interaction with the carbonaceous char. When ZnB is added to the system PC/SiR/BDP, (i) ZnB leads to a slightly enhanced PC decomposition for temperatures below 750 K; (ii) alpha-Zn-3(PO4)(2) and borophosphate (BPO4) are formed in small amounts at high temperatures suggesting a reaction between BDP and ZnB during thermal decomposition; and (iii) most of the borate remains in the solid residues, forming an amorphous pure borate network, with the BO3/BO4 ratio increasing with higher temperatures. The NMR data of thermal and fire residues are highly correlated, underlining the importance of this work for understanding the pyrolysis and flame retardancy mechanisms in the condensed phase during the burning of the PC/SiR blends. (C) 2010 Elsevier Ltd. All rights reserved. KW - Flame retardance KW - NMR KW - Polycarbonate (PC) blends KW - Bisphenol-A bis(diphenyl)phosphate (BDP) KW - Zinc borate PY - 2010 DO - https://doi.org/10.1016/j.polymdegradstab.2010.07.034 SN - 0141-3910 SN - 1873-2321 VL - 95 IS - 12 SP - 2525 EP - 2533 PB - Applied Science Publ. CY - London AN - OPUS4-22647 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Geburtig, Anja A1 - Wachtendorf, Volker A1 - Schmidt, Anita A1 - Goedecke, Thomas T1 - Combined impact of UV radiation and nitric acid on HDPE containers during outdoor exposure T1 - Kombinierte Einwirkung von UV-Strahlung und Salpetersäure auf HDPE-Behälter bei der Freibewitterung N2 - Unpigmented HDPE jerrycans filled with nitric acid (55%) and water respectively had been exposed to outdoor conditions for one Berlin summer season. As both liquids underwent equal temperature progression, exposure effects of UV radiation and nitric acid as well as of their combination can be separated and compared. On the basis of various property changes after these exposures, synergistic action is evaluated and compared to a damaged Intermediate Bulk Container (IBC) from a transport accident. It is found that carbonyl formation goes along with lightness increase in color measurement due to microcracking and with a worsening in mechanical behavior, all of them showing synergistic effects of UV and nitric acid exposure. In contrast, embedding nitrogen compounds goes along with yellowing of the material but cannot be correlated to oxidation. The reason for intensified damaging is the decomposition of the 55-percent nitric acid and formation of nitrogen oxides even at ambient temperatures, caused by UV radiation. Thus, damaging effects become similar to those caused by fuming nitric acid exposure at temperatures above 60 °C, with the result of strong oxidative degradation of the polyethylene. In contrast, exclusive exposure to the 55-percent nitric acid at 40 °C does not cause any failure. It can therefore be assumed that also the damaged IBC had been exposed to both UV radiation and nitric acid, probably outdoors. KW - Polyethylene KW - Nitric acid KW - UV radiation KW - Outdoor weathering KW - Resistance PY - 2018 DO - https://doi.org/10.3139/120.111148 SN - 0025-5300 VL - 60 IS - 3 SP - 257 EP - 264 PB - Carl Hanser Verlag CY - München AN - OPUS4-44567 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wachtendorf, Volker A1 - Geburtig, Anja T1 - Digitale Umweltsimulation am Beispiel der Photooxidation von Polymeren N2 - Die Umweltwirkungen auf ein Material werden als Überlapp der Funktionskurven von Materialempfindlichkeit und einwirkenden Umweltparametern betrachtet. Wenn entweder die Empfindlichkeit oder die Beanspruchungen Null sind, ergibt sich auch keine Umweltwirkung und bei beidseitig Werten größer Null das jeweilige Produkt der beiden. Die Akkumulation der nicht-reversiblen Effekte über die Zeit und allen Eigenschaftsänderungen entspricht der Alterung des Materials für den jeweiligen Expositionszeitraum. Die digitale Umweltsimulation gliedert sich hier in drei Teilaspekte. Ein erster, rein materialwissenschaftlicher Teil hat die Aufgabe, alle relevanten Materialempfindlichkeiten experimentell zu quantifizieren. Ein zweiter – unter Umständen numerischer Teil – hat die Aufgabe, das Bauteil und seine Einbaulage zu digitalisieren und aus den makroskopischen Umgebungsbedingungen die relevanten mikroklimatischen Umweltparameter für alle Oberflächen- oder Volumenelemente zu bestimmen. In einem dritten Teil werden die Einwirkungen über den betrachteten Zeitraum berechnet und kumuliert. Dieses Konzept, das auf den so genannten Expositions-Reaktions-Funktionen (ERF) basiert, wird an Beispielen der Photoxidation erläutert. Dieses Vorgehen wurde schon beim ViPQuali-Projekt als Numerische Umweltsimulation umgesetzt. Überprüft werden muss das Modell unbedingt an einer realitätsnahen Validierungsbeanspruchung. Hier werden die ermittelten ERFs mit über den kompletten Beanspruchungszeitraum geloggten Umweltparametern gekoppelt, um die berechnete mit der experimentell erfahrenen Alterungswirkung zu vergleichen. Nur so kann sichergestellt sein, dass alle für die Anwendungsumgebung relevanten Materialempfindlichkeiten einbezogen wurden. T2 - 52. Jahrestagung der GUS CY - Stutensee-Blankenloch, Germany DA - 26.03.2024 KW - UV KW - Polymer 3R KW - Bewitterung KW - Bestrahlung PY - 2024 SN - 978-3-9826129-0-4 SP - 31 EP - 40 PB - Gesellschaft für Umweltsimulation e.V. CY - Pfinztal (Berghausen) AN - OPUS4-59830 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wachtendorf, Volker A1 - Geburtig, Anja A1 - Schulz, Ulrich A1 - Trubiroha, Peter T1 - „Test Tailoring“ eines künstlichen Bewitterungstests am Beispiel der Entwicklung des „Acid Dew and Fog“ Testes N2 - Häufig ist es wünschenswert, für neue Materialien oder Anwendungen künstliche Bewitterungsverfahren zu benutzen, die auf die spezifischen Anforderungen besser zugeschnitten sind, als es bei bestehenden standardisierten Verfahren der Fall ist. Nachdem man die spezifischen Parameter der Beanspruchung unter Anwendungsbedingungen und die spezifische Empfindlichkeit des Materials erfasst hat, beginnt ein Prozess, der als „Test Tailoring“ häufig abstrakt verwendet, auf den aber nur selten näher eingegangen wird. Genau dieser Prozess soll hier am Beispiel der Entwicklung eines künstlichen Bewitterungstests unter saurer Beaufschlagung, dem in der BAM entwickelten Acid Dew and Fog Test, beispielhaft erläutert werden. T2 - 47. Jahrestagung der GUS 2018, Umwelteinflüsse erfassen, simulieren, bewerten CY - Pfinztal (Berghausen), Germany DA - 21.03.2018 KW - Test Tailoring KW - Bewitterung KW - Acid Dew and Fog KW - Umweltsimulation PY - 2018 VL - 47 SP - Vortrag V4, 45 EP - 54 PB - Gesellschaft für Umweltsimulation e.V. CY - Pfinztal AN - OPUS4-45412 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Geburtig, Anja A1 - Wachtendorf, Volker A1 - Trubiroha, P. T1 - Exposure response function for a quantitative prediction of weathering caused aging of polyethylene N2 - The exposure response function of the carbonyl formation over the bulk has been determined for a high-density polyethylene of a thickness of 200 μm, which was used as a weathering reference material according to ISO TR 19032. To this end, spectral sensitivity was studied by local measurement of the effect of spectrally dispersed irradiation. Both the exposure device and the methodology of determination are described. The temperature dependency of photooxidation was determined by UV exposure at various temperatures between 23 and 80 °C. Deviations from linearity and thus reciprocity below 40 °C are discussed and assumed to be related to diffusion limitations. An Arrhenius approach –based on data of linear carbonyl formation – has been incorporated into the exposure response function. Using this exposure response function, aging in terms of the distribution of a quantitative property change over a plastic component can be predicted for a specific outdoor location with real chronologic weather data as input for the exposure. Thus, artificial and natural weathering can be linked and compared. The established exposure response function has been validated by outdoor exposure results from the literature. If an estimated diffusion limitation is taken into consideration, calculations and published data are in good agreement. KW - Irradiation KW - Weathering KW - Spectral sensitivity KW - Temperature dependency KW - Spectral irradiation PY - 2019 DO - https://doi.org/10.3139/120.111348 SN - 0025-5300 VL - 61 IS - 6 SP - 517 EP - 526 PB - Carl Hanser Verlag GmbH & Co. KG AN - OPUS4-48295 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geburtig, Anja A1 - Wachtendorf, Volker A1 - Trubiroha, P. ED - Ziegahn, K.-F. T1 - Quantitative Auswertemöglichkeiten bei der spektralen Bestrahlung – Berechnung des Wirkungsspektrums N2 - Für die Bewertung des Wellenlängeneinflusses auf die Alterungsvorgänge bei der Bestrahlung UV- oder lichtempfindlicher Materialien kann die Methode der spektralen Bestrahlung angewendet werden. Im Prinzip wird dabei das linear dispergierte Spektrum einer Strahlenquelle mit kontinuierlichem Spektrum (z.B. Xe-Lampe) auf eine Probenoberfläche abgebildet, so dass Ort einer Materialänderung und Wellenlänge der Bestrahlung einander zugeordnet werden können. Nachfolgende lokal-auflösende Analysemethoden ermitteln eine Eigenschaftsänderung an einem spezifischen Ort der Probe, aus dem sich dann die Bestrahlungswellenlänge ergibt. Der verwendete Aufbau wird beschrieben. Es wird an einem ausgewählten Beispiel gezeigt, wie durch geeignete Anbindung eines Messsystems zur Bestimmung der spektralen Bestrahlungsstärke und ortsaufgelöste Messungen der Eigenschaftsänderungen eine quantitative Auswertung realisiert werden kann. Der Einfluss nichtlinearer Alterungsverläufe wird diskutiert. Grenzen der Methode werden aufgezeigt und Erweiterungsmöglichkeiten dargestellt. T2 - 46. Jahrestagung der GUS CY - Stutensee-Blankenloch, Germany DA - 22.03.2017 KW - UV-Bestrahlung PY - 2017 SN - 978-3-9816286-9-2 SP - V 8, 91 EP - 99 AN - OPUS4-42578 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 - JOUR A1 - Radunz, Sebastian A1 - Kraus, Werner A1 - Bischoff, F. A. A1 - Emmerling, Franziska A1 - Resch-Genger, Ute A1 - Tschiche, Harald T1 - Temperature- and Structure-Dependent Optical Properties and Photophysics of BODIPY Dyes N2 - We report on the temperature- and structural-dependent optical properties and photophysics of a set of boron dipyrromethene (BODIPY) dyes with different substitution patterns of their meso-aryl subunit. Single-crystal Xray diffraction analysis of the compounds enabled a classification of the dyes into a sterically hindered and a unhindered group. The steric hindrance refers to a blocked rotational motion of the aryl subunit around the bond connecting this moiety to the meso-position of the BODIPY core. The energy barriers related to this rotation were simulated by DFT calculations. As follows from the relatively low rotational barrier calculated to about 17 kcal/mol, a free rotation is only possible for sterically unhindered compounds. Rotational barriers of more than 40 kcal/mol determined for the sterically hindered compounds suggest an effective freezing of the rotational motion in These molecules. With the aid of temperature-dependent spectroscopic measurements, we could show that the ability to rotate directly affects the optical properties of our set of BODIPY dyes. This accounts for the strong temperature dependence of the fluorescence of the sterically unhindered compounds which show a drastic decrease in fluorescence quantum yield and a significant shortening in fluorescence lifetime upon heating. The optical properties of the sterically hindered compounds, however, are barely affected by temperature. Our results suggest a nonradiative deactivation of the first excited singlet state of the sterically unhindered compounds caused by a conical intersection of the potential energy surfaces of the Ground and first excited state which is accessible by rotation of the meso-subunit. This is in good agreement with previously reported deactivation mechanisms. In addition, our results suggest the presence of a second nonradiative depopulation pathway of the first excited singlet state which is particularly relevant for the sterically hindered compounds. KW - Fluorescence KW - Sensor KW - Switch KW - pH KW - BODIPY KW - Dye KW - Probe KW - Synthesis KW - Photophysics KW - Mechanism PY - 2020 DO - https://doi.org/10.1021/acs.jpca.9b11859 SN - 1089-5639 VL - 124 IS - 9 SP - 1787 EP - 1797 PB - American Chemical Society AN - OPUS4-50639 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - de Olivera, Paulo A1 - Michalchuk, Adam A1 - Marquardt, Julien A1 - Feiler, Torvid A1 - Prinz, Carsten A1 - Torresi, R. A1 - Camargo, P. A1 - Emmerling, Franziska T1 - Investigating the role of reducing agents on mechanosynthesis of Au nanoparticles N2 - Control over the bottom up synthesis of metal nanoparticles (NP) depends on many experimental factors, including the choice of stabilising and reducing agents. By selectively manipulating these species, it is possible to control NP characteristics through solution-phase synthesis strategies. It is not known, however, whether NPs produced from mechanochemical syntheses are governed by the same rules. Using the Au NPs mechanosynthesis as a model system, we investigate how a series of common reducing agents affect both the reduction kinetics and size of Au NPs. It is shown that the relative effects of reducing agents on mechanochemical NP synthesis differ significantly from their role in analogous solution-phase reactions. Hence, strategies developed for control over NP growth in solution are not directly transferrable to environmentally benign mechanochemical approaches. This work demonstrates a clear need for dedicated, systematic studies on NP mechanosynthesis. KW - Mechanochemistry KW - Metal nanoparicels PY - 2020 DO - https://doi.org/10.1039/d0ce00826e VL - 22 IS - 38 SP - 6261 EP - 6267 PB - Royal Society of Chemistry AN - OPUS4-51757 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kulla, Hannes A1 - Haferkamp, Sebastian A1 - Akhmetova, Irina A1 - Röllig, Mathias A1 - Maierhofer, Christiane A1 - Rademann, Klaus A1 - Emmerling, Franziska T1 - In situ investigations of mechanochemical one-pot syntheses N2 - We present an in situ triple coupling of synchrotron X-ray diffraction with Raman spectroscopy, and thermography to study milling reactions in real time. This combination of methods allows a correlation of the structural evolution with temperature information. The temperature information is crucial for understanding both the thermodynamics and reaction kinetics. The reaction mechanisms of three prototypical mechanochemical syntheses, a cocrystal formation, a C@C bond formation (Knoevenagel condensation), and the formation of a manganese-phosphonate, were elucidated. Trends in the temperature development during milling are identified. The heat of reaction and latent heat of crystallization of the product contribute to the overall temperature increase. A decrease in temperature occurs via release of, for example, water as a byproduct. Solid and liquid intermediates are detected. The influence of the mechanical impact could be separated from temperature effects caused by the reaction. KW - In situ studies KW - Mechanochemistry KW - Raman spectroscopy KW - Thermography KW - X-ray diffraction PY - 2018 DO - https://doi.org/10.1002/anie.201800147 SN - 1433-7851 SN - 1521-3773 VL - 57 IS - 20 SP - 5930 EP - 5933 PB - Wiley-VCH CY - Weinheim AN - OPUS4-44946 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Haferkamp, Sebastian A1 - Emmerling, Franziska T1 - Insights into the mechanochemical Knoevenagel condensation N2 - Mechanochemistry paves the way to simple, fast, and green syntheses, but there is a lack in understanding of the underlying mechanisms. Here, we present a universal strategy for simultaneous real-time in situ analysis, combining X-ray diffraction, Raman spectroscopy, and thermography. T2 - Bessy User Meeting 2019 CY - Berlin, Germany DA - 05.12.2019 KW - Mechanochemistry PY - 2019 AN - OPUS4-50122 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - May, Anastasia T1 - Thermomechanochemical Synthesis of Pimelic Acid Cocrystals N2 - Milling temperature is a critical factor in mechanochemistry, affecting the kinetics and outcomes of reactions. In the context of cocrystallization, the influence of milling temperature on the process has been investigated for cocrystal systems pyrazinamide:pimelic acid (PZA:PA) and 4,4'-bipyridine:pimelic acid (BPY:PA). By means of temperature-controlled milling, stabilization of metastable polymorph of PZA:PA was achieved, thereby decelerating the aging process of the polymorph. This was accomplished through controlled heated milling of PZA and PA. Furthermore, we have successfully synthesized all three BPY:PA polymorphs by mechanochemistry involving controlled cooled and heated milling. In previous studies, only the most stable polymorph was obtained by mechanochemistry. T2 - 10th European Crystallography School CY - Ohrid, North Macedonia DA - 23.06.2025 KW - Mechanochemistry KW - Cocrystal PY - 2025 AN - OPUS4-63797 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Al-Terkawi, Abdal-Azim A1 - Scholz, G. A1 - Emmerling, Franziska A1 - Kemnitz, E. T1 - Strontium-coordination polymers based on tetrafluorophthalic and phthalic acids: mechanochemical synthesis, ab initio structures determination, and spectroscopic characterization N2 - Two strontium-based dicarboxylate systems [Sr(oBDC-F4)(H2O)2] (1) and [{Sr(oBDC)(H2O)2)·H2O] (2) were synthesized mechanochemically via milling of Sr(OH)2·8H2O with tetrafluorophthalic acid (H2oBDC-F4) or phthalic acid (H2oBDC), respectively. The new structures were determined ab initio from the powder X-ray diffraction (PXRD) data. Both compounds 1 and 2 crystallize in the monoclinic space group P21 /c as two-dimensional coordination polymers (2D-CPs). The determined structures were validated by extended X-ray absorption (EXAFS) data. Compounds 1 and 2 show different thermal stabilities. The fluorinated CP 1 is decomposed at 300 °C while the nonfluorinated CP 2 transforms into a new phase after thermal treatment at 400 °C. The two hydrated CPs exhibit small surface areas which increase after the thermal posttreatment for 1 but remains unchanged for the dehydrated sample of 2. Dynamic vapor sorption (DVS) experiments indicate that both the dehydrated and hydrated samples of 2 depict no significant differences in their adsorption isotherms. The DVS of water indicates that the phase transition after thermal posttreatment of 2 is irreversible. KW - Mechanochemistry KW - XRD KW - NMR PY - 2017 DO - https://doi.org/10.1039/c7dt02564e SN - 1477-9226 SN - 1477-9234 VL - 46 IS - 37 SP - 12574 EP - 12587 PB - The Royal Society of Chemistry CY - Cambridge AN - OPUS4-42261 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heilmann, Maria T1 - Synthesis of bimetallic nickel nanoparticles as catalysts for the Sabatier reaction N2 - Nanoparticles (NPs) have become important materials for a variety of chemical technologies. The enhanced surface-area-to-volume ratio of NPs, making them excellent for use as catalyst, in analytical assays, and for antimicrobial applications. Nickel NPs have exhibited immense potential as important catalyst for the Sabatier reaction, i.e. converting waste to energy via transformation of CO2 into CH4, and could replace the rare earth elements such as Ru, PT, or Rh. In this work we describe the solvothermal synthesis of monometallic and bimetallic nickel nanoparticles. Monodisperse monometallic Ni NPs were synthesized using Oleylamin as solvent and reducing agent. The nanoparticles were investigated using small angle scattering (SAXS), scanning transmission electron microscopy (STEM) and energy dispersive X-ray spectroscopy (EDX), showing that the NPs are stable while the surface is not entirely covered. However, Ni has a high propensity to undergo oxidation, and becoming deactivated by coke formation. Hence, we further explore the preparation of bimetallic NPs, where a second metal is added to stabilize the Ni. Bimetallic Cu-Ni NPs were synthesized by simultaneous solvothermal reduction. These bimetallic NPs exhibit excellent catalytic properties are promising candidates to be used as catalysts for efficient energy storage. T2 - Adlershofer Forschungsforum 2019 CY - Berlin, Germany DA - 11.11.2019 KW - Nanoparticles KW - Catalysis KW - Synthesis PY - 2019 AN - OPUS4-50173 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tuma, Dirk A1 - Mady, A. H. A1 - Baynosa, M. L. A1 - Saad, M. A1 - Dhakal, G. A1 - Kim, W. K. A1 - Shim, Jae-Jin T1 - Morphology-engineered hollow NiTiO₃/C–Ag/Ag₃PO₄ S-scheme heterojunction photocatalyst: mechanistic insights into sunlight-driven tetracycline degradation N2 - Tetracycline (TCH), a widely used antibiotic, persists in aquatic and terrestrial environments, posing ecological risks and accelerating antibiotic resistance. To address this, we report a hollow-structured NiTiO₃/C–Ag/Ag₃PO₄ (NT/C–AAP) photocatalyst—the first hollow-type nickel titanate—synthesized via a self-template solvothermal route followed by photodeposition. The catalyst integrates key design strategies—hollow architecture, oxygen vacancies, carbon coating, and an S-scheme heterojunction—to optimize photocatalytic performance. The hollow structure enhances light harvesting via internal scattering, oxygen vacancies facilitate O2 adsorption and superoxide (O₂•⁻) generation, and the S-scheme heterojunction effectively suppresses electron–hole recombination while preserving strong redox potential. NT/C–AAP achieved 96% TCH degradation within 1 h and 82% mineralization in 3 h under solar light, far exceeding core–shell (18%) and aggregated (47%) NiTiO₃-based catalysts. Complete removal was realized within 40 min under 400 W visible light. The catalyst maintained 96% activity after five cycles, confirming excellent durability. Compared with previously reported NiTiO₃ photocatalysts, NT/C–AAP delivered a 50–400% performance enhancement arising from its engineered hollow structure and improved electronic properties. Mechanistic studies identified O₂•⁻ and •OH radicals as dominant species, validating the role of morphology and interface engineering in directing charge separation and redox activity. Additionally, a catalyst performance index was proposed to facilitate comparison across diverse conditions. Overall, this work introduces a novel, durable photocatalyst that links structural design to functional performance and demonstrates strong potential for practical environmental remediation. KW - Heterojunction photocatalyst KW - Photodegradation KW - Tetracycline PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655946 DO - https://doi.org/10.1007/s42114-025-01600-x SN - 2522-0128 VL - 9 IS - 2 SP - 1 EP - 19 PB - Springer Nature CY - London AN - OPUS4-65594 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schwibbert, Karin A1 - de Eulate Pérez, Elisa García A1 - Wen, Keqing A1 - Voss, Heike A1 - Thiele, Dorothea A1 - Richter, Anja M. A1 - Bonse, Jörn T1 - Escherichia coli repellence via laser-induced periodic surface structures (LIPSS) on titanium: Critical role of biofilm-associated gene expression N2 - The inconsistency in the observed bacteria-repellent effects of laser-induced surface textures remains a subject of scientific debates. With E. coli TG1 as test strain, we performed biofilm formation assays on ultrashort pulse laser textured titanium. Samples covered with low spatial frequency LIPSS (LSFL) of periods around 750 nm or with high spatial frequency LIPSS (HSFL) featuring smaller periods around 100 nm were processed on polished samples. While LSFL significantly reduce the number of adhering bacteria compared to the polished reference, HSFL do not. Simultaneously, we concentrate our study on bacterial strategies employed for biofilm formation, that is the transcription of the biofilm-associated genes csgB, involved in primary adhesion to a surface, and wza, participating in biofilm maturation. Promoter regions of these genes were cloned into a promotor probe plasmid with the green fluorescent protein GFP+ as reporter and transferred into the test strain. As indicated by the fluorescence intensity of the reporter protein, among the bacteria colonizing LSFL-covered areas, a markedly higher proportion of cells transcribing csgB or wza were detected, compared to the bacterial populations colonizing the polished or HSFL-covered areas. To our knowledge, this is the first study indicating that the antifouling effect of LSFL topographies can be counteracted when bacteria activate biofilm-associated genes. KW - Laser-induced periodic surface structures (LIPSS) KW - Titanium KW - Biofilm KW - Antifouling KW - Gene expression KW - Fluorescence microscopy PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655572 DO - https://doi.org/10.1016/j.apsusc.2026.166363 SN - 0169-4332 VL - 730 SP - 1 EP - 9 PB - Elsevier B.V. AN - OPUS4-65557 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gugin, Nikita A1 - Villajos Collado, José Antonio A1 - Dautain, O. A1 - Maiwald, Michael A1 - Emmerling, Franziska T1 - Optimizing the Green Synthesis of ZIF-8 by Reactive Extrusion Using In Situ Raman Spectroscopy 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. KW - Mechanochemistry KW - In situ Raman KW - Large-scale processing KW - Metal−organic frameworks KW - Twin-screw extrusion (TSE) PY - 2023 DO - https://doi.org/10.1021/acssuschemeng.2c07509 SN - 2168-0485 VL - 11 IS - 13 SP - 5175 EP - 5183 PB - ACS Publications AN - OPUS4-57366 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Božičević, Lucija A1 - Altmann, Korinna A1 - Hildebrandt, Jana A1 - Knigge, Xenia A1 - Vrček, Valerije A1 - Peranić, Nikolina A1 - Kalcec, Nikolina A1 - Vinkovic Vrcek, Ivana T1 - Estrogenic activity of plastic nanoparticles mixture under in vitro settings N2 - The plastic value chain, central part of modern living, caused environmental pollution and bioaccumulation of plastic nanoparticles (PNPs). Their ubiquitous presence in different environmental and biological compartments has become a serious threat to human health and ecosystems. Frequently used plastic materials such as polypropylene (PP), polystyrene (PS) and polyethylene (PE) have been detected in the form of PNPs in the food chain, soil, water and air, as well as in human feces and blood. In this study, we aimed to provide novel insights in endocrine disrupting properties of PNPs using in vitro estrogen receptor (ER) transactivation assay. The effects of PP-NPs, PE-NPs and PS-NPs and their mixture on T47D-KBluc cell line stably transfected with luciferase as reporter enzyme was evaluated by means of cytotoxicity, cellular uptake and ER activation. Tested dose range for PNPs was 0.001 – 10 mg/L. Both cellular uptake and cytotoxicity for all PNPs was found to be dose-dependent. Only the highest dose of PP-NPs and PE-NPs induced apoptosis and cell death, while PS-NPs were not cytotoxic in tested dose range. For tested concentrations, PP-NPs and PE-NPs showed significant agonistic activity on ER, while PS-NPs cannot be considered ER active. When, applied as mixture, PNP demonstrated additive toxicity effects compared to the effect of each individual PNPs. Additivity was also observed for ER agonistic effect of PNPs mixture according to the benchmark dose-addition modelling approach. This study provides missing science-based evidence on endocrine disrupting effects of PE-NPs, PP-NPs, PS-NPs and their mixtures and highlights the importance of considering unintentional, aggregate and combined exposure to different PNPs in risk management. KW - Risk assessment KW - Nanoplastics KW - Estrogenic activity of plastic nanoparticles PY - 2024 DO - https://doi.org/10.1039/D3EN00883E SN - 2051-8153 VL - 11 IS - 5 SP - 2112 EP - 2126 PB - Royal Society of Chemistry (RSC) AN - OPUS4-59724 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -