TY - JOUR A1 - Böhning, Martin A1 - Tidjani, Adams A1 - Wald, Oliver A1 - Brzezinka, Klaus-Werner A1 - Turky, Gamal A1 - Goering, Harald A1 - Schartel, Bernhard A1 - Schönhals, Andreas T1 - Dielectric and gas transport properties of polypropylene-clay nanocomposites T2 - Frühjahrstagung des Arbeitskreises Festkörperphysik bei der DPG CY - Regensburg, Germany DA - 2002-03-11 PY - 2002 SN - 0420-0195 SN - 0372-5448 SN - 0343-9216 IS - CPP 5.4 SP - 425 CY - Bad Honnef AN - OPUS4-2036 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schartel, Bernhard A1 - Frasca, Daniele A1 - Schulze, Dietmar A1 - Wachtendorf, Volker A1 - Krafft, Bernd A1 - Morys, Michael A1 - Böhning, Martin A1 - Rybak, Thomas T1 - Multilayer graphene rubber nanocomposites N2 - Multilayer Graphene (MLG), a nanoparticle with a specific surface of BET = 250 m²/g and thus made of only approximately 10 graphene sheets, is proposed as a nanofiller for rubbers. When homogenously dispersed, it works at low loadings enabling the replacement of carbon black (CB), increase in efficiency, or reduction in filler concentration. Actually the appropriate preparation yielded nanocomposites in which just 3 phr are sufficient to significantly improve the rheological, curing and mechanical properties of different rubbers, as shown for Chlorine-Isobutylene-Isoprene Rubber (CIIR), Nitrile-Butadiene Rubber (NBR), Natural Rubber (NR), and Styrene-Butadiene Rubber (SBR). A mere 3 phr of MLG tripled the Young’s modulus of CIIR, an effect equivalent to 20 phr of carbon black. Similar equivalents are observed for MLG/CB mixtures. MLG reduces gas permeability, increases thermal and electrical conductivities, and retards fire behavior. The later shown by the reduction in heat release rate in the cone calorimeter. The higher the nanofiller concentration is (3 phr, 5 phr, and 10 phr was investigated), the greater the improvement in the properties of the nanocomposites. Moreover, the MLG nanocomposites improve stability of mechanical properties against weathering. An increase in UV-absorption as well as a pronounced radical scavenging are proposed and were proved experimentally. To sum up, MLG is interesting as a multifunctional nanofiller and seems to be quite ready for rubber development. T2 - TOP 2016, VIII International Conference on “Times of Polymers and Composites” CY - Naples, Italy DA - 19.06.2016 KW - Graphene KW - Nanocomposite KW - Rubber PY - 2016 SN - 978-0-7354-1390-0 DO - https://doi.org/10.1063/1.4949621 SN - 0094-243X SN - 1551-7616 VL - 1736 SP - 020046, 1 EP - 4 PB - AIP AN - OPUS4-36864 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schartel, Bernhard T1 - Multilayer graphene rubber nanocomposites N2 - Multilayer Graphene (MLG), a nanoparticle with a specific surface of BET = 250 m2/g and thus made of only approximately 10 graphene sheets, is proposed as a nanofiller for rubbers. When homogenously dispersed, it works at low loadings enabling the replacement of carbon black (CB), increase in efficiency, or reduction in filler concentration. Actually the appropriate preparation yielded nanocomposites in which just 3 phr are sufficient to significantly improve the rheological, curing and mechanical properties of different rubbers, as shown for Chlorine-Isobutylene-Isoprene Rubber (CIIR), Nitrile-Butadiene Rubber (NBR), Natural Rubber (NR), and Styrene-Butadiene Rubber (SBR). A mere 3 phr of MLG tripled the Young’s modulus of CIIR, an effect equivalent to 20 phr of carbon black. Similar equivalents are observed for MLG/CB mixtures. MLG reduces gas permeability, increases thermal and electrical conductivities, and retards fire behavior. The later shown by the reduction in heat release rate in the cone calorimeter. The higher the nanofiller concentration is (3 phr, 5 phr, and 10 phr was investigated), the greater the improvement in the properties of the nanocomposites. Moreover, the MLG nanocomposites improve stability of mechanical properties against weathering. An increase in UV-absorption as well as a pronounced radical scavenging are proposed and were proved experimentally. To sum up, MLG is interesting as a multifunctional nanofiller and seems to be quite ready for rubber development. T2 - 8th Conference on Times of Polymers (TOP) & Composites CY - Ischia, Italy DA - 19.06.2016 KW - Graphene KW - Rubber KW - Nanocomposite PY - 2016 AN - OPUS4-36869 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sut, Aleksandra A1 - Greiser, Sebastian A1 - Jäger, Christian A1 - Schartel, Bernhard T1 - Synergy in flame-retarded epoxy resin - Identification of chemical interactions by solid-state NMR N2 - The potential synergists aluminium diethylphosphinate (AlPi), boehmite (AlO(OH)) and melamine polyphosphate (MPP) were compared in flame-retardant epoxy resin (EP)/melamine poly(magnesium phosphate) (S600). The pyrolysis, the fire behaviour as well as the chemical interactions in the gas and condensed phases were investigated by various methods. Flammability was investigated by cone calorimeter and oxygen index (OI). The thermal and thermo-oxidative decomposition were studied by thermogravimetric analysis coupled with FTIR spectrometer. The special focus was on the Investigation of structural changes in the condensed phase via solid-state NMR of 27Al and 31P nuclei. By the comparison of epoxy resin with only one additive or with S600 in combination with AlPi, AlO(OH) or MPP, it was possible to calculate the synergy index. The best performance in terms of fire behaviour was observed for EP/S600/MPP with a PHRR (Peak heat release rate) of 208 kW m-2 due to slight synergy. In the case of THE (total heat evolved), clear synergy occurred for EP/S600/AlPi and EP/S600/AlO(OH). By solid-state NMR, different phosphates and aluminates were identified, indicating the chemical interactions between S600 and AlPi, AlO(OH) or MPP. The systematic multi-methodical approach yielded insight into the synergistic effects in the flame-retarded epoxy resin. KW - Synergy KW - Epoxy resin KW - Flame retardancy KW - Melamine poly(magnesium phosphate) KW - Solid-state NMR PY - 2017 DO - https://doi.org/10.1007/s10973-016-5934-4 SN - 1388-6150 SN - 1588-2926 VL - 128 IS - 1 SP - 141 EP - 153 PB - Springer AN - OPUS4-39298 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sut, Aleksandra A1 - Greiser, Sebastian A1 - Jäger, Christian A1 - Schartel, Bernhard T1 - Aluminium diethylphosphinate versus ammonium polyphosphate: A comprehensive comparison of the chemical interactions during pyrolysis in flame-retarded polyolefine/poly(phenylene oxide) N2 - A systematic comparison of chemical interactions and fire behaviour is presented for the thermoplas-tic elastomer (block copolymer styrene-ethylene-butadiene-styrene) (TPE-S)/diethyl- and methylvinylsiloxane (Si)/poly(phenylene oxide) (PPO), flame-retarded with aluminium diethylphosphinate (AlPi)and with ammonium polyphosphate (APP), respectively. TPE-S/APP/Si/PPO performed better in the conecalorimeter test (reduction in peak heat release rate from 2042 to 475 kW m−2), but TPE-S/AlPi/Si/PPO inthe flammability tests (oxygen index (OI) and UL 94). This difference was caused by the different modes ofaction of APP (more in the condensed phase) and AlPi (mainly in the gas phase). Thermogravimetry cou-pled with Fourier transform infrared spectroscopy (TG-FTIR) was used to analyse the mass loss and theevolved gas products, while a Linkam hot-stage cell to investigate the decomposition in the condensedphase. Moreover, a detailed analysis of the fire residues was done using solid-state NMR.13C MAS NMRshowed that both flame-retarded compositions form graphite-like amorphous carbonaceous char, orig-inating from PPO.31P MAS NMR and29Si MAS NMR delivered important information about interactionbetween phosphorus and the siloxane. For TPE-S/AlPi/Si/PPO aluminium phosphate and silicon dioxideoccurred, while also silicophosphate was produced in TPE-S/APP/Si/PPO. The direct comparison of two ofthe most prominent halogen-free flame retardants containing phosphorus delivered meaningful insightsinto the modes of action and molecular mechanisms controlling flame retardancy. KW - Aluminium diethylphosphinate KW - Ammonium polyphosphate KW - Flame retardancy KW - Solid-state NMR KW - SEBS PY - 2016 SN - 0040-6031 SN - 1872-762X VL - 640 SP - 74 EP - 84 PB - Elsevier AN - OPUS4-37802 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Langfeld, Kirsten A1 - Wilke, Antje A1 - Sut, Aleksandra A1 - Greiser, Sebastian A1 - Ulmer, B. A1 - Andrievici, V. A1 - Limbach, P. A1 - Bastian, Martin A1 - Schartel, Bernhard T1 - Halogen-free fire retardant styrene-ethylene-butylene-styrene-based thermoplastic elastomers using synergistic aluminium diethylphosphinate-based combinations N2 - Multicomponent flame retardant systems containing aluminum diethylphosphinate in thermoplastic styrene–ethylene–butylene–styrene elastomers are investigated (oxygen index, UL 94, cone calorimeter, and mechanical testing). Solid-state nuclear magnetic resonance, scanning electron microscopy, and elemental analysis illuminate the interactions in the condensed phase. Thermoplastic styrene–ethylene–butylene–styrene elastomers are a challenge for flame retardancy (peak heat release rate at 50 kW m-2 > 2000 kW m-2, oxygen index = 17.2 vol%, no UL-94 horizontal burn rating) since it burns without residue and with a very high effective heat of combustion. Adding aluminum diethylphosphinate results in efficient flame inhibition and improves the reaction to small flame, but it is less effective in the cone calorimeter. Its efficacy levels off for amounts >~25 wt%. As the most promising synergistic system, aluminum diethylphosphinate/melamine polyphosphate was identified, combining the main gas action of aluminum diethylphosphinate with condensed phase mechanisms. The protection layer was further improved with several adjuvants. Keeping the overall flame retardant content at 30 wt%, aluminum diethylphosphinate/melamine polyphosphate/titanium dioxide and aluminum diethylphosphinate/melamine polyphosphate/boehmite were the best approaches. An oxygen index of up to 27 vol% was achieved and a horizontal burn rating in UL 94 with immediate self-extinction; peak heat release rate decreased by up to 85% compared to thermoplastic styrene–ethylene–butylene–styrene elastomers, to <300 kW m-2. KW - Flame retardancy KW - Aluminium phosphinate KW - Thermoplastic elastomers KW - Cone calorimetry KW - Flammability PY - 2015 DO - https://doi.org/10.1177/0734904114565581 SN - 0734-9041 SN - 1530-8049 VL - 33 IS - 2 SP - 157 EP - 177 PB - Sage CY - London AN - OPUS4-32692 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Strommer, Bettina A1 - Battig, Alexander A1 - Schulze, Dietmar A1 - Agudo Jácome, Leonardo A1 - Schartel, Bernhard A1 - Böhning, Martin T1 - Shape, orientation, interaction, or dispersion: valorization of the influence factors in natural rubber nanocomposites N2 - The addition of nanoparticles as reinforcing fillers in elastomers yields nanocomposites with unique property profiles, which opens the door for various new application fields. Major factors influencing the performance of nanocomposites are studied by varying the type and shape of nanoparticles and their dispersion in the natural rubber matrix. The industrial applicability of these nanocomposites is put into focus using two types of graphene and a nanoscale carbon black, all commercially available, and scalable processing techniques in the form of a highly filled masterbatch production via latex premixing by simple stirring or ultrasonically assisted dispersing with surfactant followed by conventional two-roll milling and hot pressing. Different processing and measurement methods reveal the potential for possible improvements: rheology, curing behavior, static and dynamic mechanical properties, swelling, and fire behavior. The aspect ratio of the nanoparticles and their interaction with the surrounding matrix prove to be crucial for the development of superior nanocomposites. An enhanced dispersing method enables the utilization of the improvement potential at low filler loadings (3 parts per hundred of rubber [phr]) and yields multifunctional rubber nanocomposites: two-dimensional layered particles (graphene) result in anisotropic material behavior with strong reinforcement in the in-plane direction (157% increase in the Young's modulus). The peak heat release rate in the cone calorimeter is reduced by 55% by incorporating 3 phr of few-layer graphene via an optimized dispersing process. KW - Graphene KW - Natural rubber KW - Nanocomposites KW - Anisotropy KW - Fire behavior PY - 2023 DO - https://doi.org/10.5254/rct.23.77961 SN - 0035-9475 SN - 1943-4804 VL - 96 IS - 1 SP - 40 EP - 58 PB - Allen Press CY - Lawrence (KA), USA AN - OPUS4-57568 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sunder, S. A1 - Jauregui Rozo, Maria A1 - Deshpande, H. A1 - Neyer, A. A1 - Papaiya, V. A1 - Meinel, Dietmar A1 - Schartel, Bernhard A1 - Ruckdäschel, H. T1 - Char to the Rescue: Processing and Transfer of Flame-Retardant Epoxy Resins, Adjusting the Fire Behavior and Post-Fire Structural Integrity of Glass Fiber Composites N2 - Epoxy (EP) glass fiber reinforced composites (GFRCs) are extensively used in structural applications due to their excellent thermal and mechanical properties, but their inherent flammability limits fire-safe deployment. While numerous studies examine the flame retardancy of resins or individual composite systems, comprehensive studies evaluating simultaneous improvements in flame retardancy and post-fire mechanical integrity, specifically through prepreg processing, remain challenging. This study investigates the effectiveness and transferability of phosphorus-based flame retardant (FR) systems to diglycidyl ether of bisphenol A (DGEBA) and EP novolac resin matrices and their corresponding bidirectional glass fiber composites via prepregs. The FRs are chosen based on varying modes of action: ammonium polyphosphate with inorganic silicate (APP/InSi) primarily acts in the condensed phase (CP), and aluminum diethyl phosphinate with zinc hydroxystannate (AldietPO2/ZHS) is known to demonstrate both gas-phase (GP) and CP activity. Fire residues are tailored to compensate for structural defects from fire exposure. EP novolac, with higher aromaticity and cross-linking, possesses better inherent flame resistance compared to DGEBA. The novolac composites containing AldietPO2/ZHS simultaneously showed the highest retention of flexural properties after fire exposure and the best fire safety index. The experimental values of the post-fire flexural properties in the composites calibrated damage parameters in two theoretical models. KW - Composites KW - DGEBA KW - Epoxy novolac KW - Post-fire KW - Prepregs PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643752 DO - https://doi.org/10.1002/pol.20250692 SN - 2642-4169 SN - 2642-4150 VL - 63 IS - 20 SP - 4295 EP - 4309 PB - Wiley AN - OPUS4-64375 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rockel, Daniel A1 - Sanchez Olivares, G. A1 - Calderas, F. A1 - Schartel, Bernhard T1 - Two heads are better than one: Aluminum trihydroxide / phosphorous flame retardant combination in natural waste fiber biocomposites N2 - Future polymeric materials that replace fossil fuel-based engineering plastics demand the use of renewable sources as well as the implementation of key properties such as flame retardancy, processing, and mechanical properties. This study focuses on the combination of aluminum trihydroxide (ATH) and phosphorus-based flame retardants in compositable thermoplastic starch reinforced with sustainable multifunctional leather waste fibers. The flame retardants engender different flame-retardant modes of action, improving overall performance when combined. The partial substitution of ATH with phosphorous flame retardant allowed a reduction in flame retardant loading. Materials with 90 phr of ATH reached a limiting oxygen index of 31.5 vol.-% and a UL-94 rating of V-1, whereas the combination of 73 phr ATH and 7 phr of diphenyl ocytyl phosphate achieved a V-0 rating and a slightly reduced peak of heat release rate. This study demonstrates the potential of multicomponent systems implementing waste fiber–reinforced biocomposites. KW - Biocomposites KW - Flame retardancy KW - Phosphorous flame retardants KW - Synergism KW - Sustainability PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639084 DO - https://doi.org/10.1016/j.polymertesting.2025.108938 SN - 0142-9418 SN - 1873-2348 VL - 150 SP - 1 EP - 17 PB - Elsevier Ltd. AN - OPUS4-63908 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krebs, N. A1 - Demleitner, M. A1 - Albuquerque, R.Q. A1 - Schartel, Bernhard A1 - Ruckdäschel, H. T1 - Bayesian Optimization of flame-retardant performance in a high-Tg epoxy resin system N2 - Polymeric materials are widely used due to their mechanical properties and cost-effectiveness, but their inherent flammability requires effective flame-retardant additives to meet safety standards. Optimizing multicomponent flame-retardant formulations is challenging due to the vast experimental space. This study applies Bayesian Optimization (BO) to optimize flame-retardant formulations in high glass transition temperature (Tg) epoxy resins. Aluminum diethyl phosphinate (AlPi) was systematically combined with three synergists: zinc stannate (ZnSt), a silicone-based additive (DowSil), and low-melting glass frits (Ceepree). BO-guided experimental design expanded from 16 initial formulations to a total of 28, minimizing the Maximum Average Rate of Heat Emission (MARHE) under the constraint of Total Smoke Production (TSP) < 17 m2 using the epsilon-constraint method. BO revealed non-linear synergistic interactions: ZnSt significantly reduced smoke production while AlPi effectively lowered heat release. The optimized formulation (BO7) achieved the lowest MARHE (122 kW/m2) while maintaining acceptable smoke levels, establishing a new Pareto front. The results demonstrate the effectiveness of BO in accelerating the development of synergistic, halogen-free flame-retardant polymer systems, offering a scalable and sustainable approach to polymer formulation design. KW - Machine learning KW - Epoxy resin KW - Bayesian optimization KW - Flame retardancy KW - Cone calorimeter PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641070 DO - https://doi.org/10.1016/j.commatsci.2025.114210 SN - 0927-0256 SN - 1879-0801 VL - 260 SP - 1 EP - 9 PB - Elsevier AN - OPUS4-64107 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -