TY - JOUR A1 - Frasca, Daniele A1 - Schulze, Dietmar A1 - Wachtendorf, Volker A1 - Morys, Michael A1 - Schartel, Bernhard T1 - Multilayer graphene/chlorine-isobutene-isoprene rubber nanocomposites: the effect of dispersion JF - Polymers for Advanced Technologies N2 - Multilayer graphene (MLG) is composed of approximately 10 sheets of graphene. It is a promising nanofiller just starting to become commercially available. The Dispersion of the nanofiller is essential to exploit the properties of the nanocomposites and is dependent on the preparation method. In this study, direct incorporation of 3 parts per hundred of rubber (phr) MLG into chlorine-isobutene- isoprene rubber (CIIR) on a two-roll mill did not result in substantial enhancement of the material properties. In contrast, by pre-mixing the MLG (3 phr) with CIIR using an ultrasonically assisted solution mixing procedure followed by two-roll milling, the properties (rheological, curing, and mechanical) were improved substantially compared with the MLG/CIIR nanocomposites mixed only on the mill. The Young’s moduli of the nanocomposites mixed in solution increased by 38%. The CIIR/MLG nanocomposites produced via solution showed superior durability against weathering exposure. KW - Multilayer graphene KW - Nanocomposite KW - Dispersion KW - Rubber PY - 2016 DO - https://doi.org/10.1002/pat.3740 SN - 1042-7147 SN - 1099-1581 VL - 27 IS - 7 SP - 872 EP - 881 PB - Wiley AN - OPUS4-36866 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Frasca, Daniele A1 - Schulze, Dietmar A1 - Wachtendorf, Volker A1 - Krafft, Bernd A1 - Rybak, Thomas A1 - Schartel, Bernhard T1 - Multilayer Graphene/Carbon Black/Chlorine Isobutyl Isoprene Rubber Nanocomposites JF - Polymers N2 - High loadings of carbon black (CB) are usually used to achieve the properties demanded of rubber compounds. In recent years, distinct nanoparticles have been investigated to replace CB in whole or in part, in order to reduce the necessary filler content or to improve performance. Multilayer graphene (MLG) is a nanoparticle made of just 10 graphene sheets and has recently become commercially available for mass-product nanocomposites. Three phr (part for hundred rubbers) of MLG are added to chlorine isobutyl isoprene rubber (CIIR)/CB composites in order to replace part of the CB. The incorporation of just 3 phr MLG triples the Young’s modulus of CIIR; the same effect is obtained with 20 phr CB. The simultaneous presence of three MLG and CB also delivers remarkable properties, e.g. adding three MLG and 20 phr CB increased the hardness as much as adding 40 phr CB. A comprehensive study is presented, showing the influence on a variety of mechanical properties. The potential of the MLG/CB combination is illustrated to reduce the filler content or to boost performance, respectively. Apart from the remarkable mechanical properties, the CIIR/CB/MLG nanocomposites showed an increase in weathering resistance. KW - nanocomposites KW - rubber KW - multilayer graphene KW - carbon black PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-358569 DO - https://doi.org/10.3390/polym8030095 SN - 2073-4360 VL - 8 SP - 95 PB - MDPI CY - Basel, Switzerland AN - OPUS4-35856 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 JF - AIP Conference Proceedings 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 - JOUR A1 - Frasca, Daniele A1 - Schulze, Dietmar A1 - Wachtendorf, Volker A1 - Huth, Christian A1 - Schartel, Bernhard T1 - Multifunctional multilayer graphene/elastomer nanocomposites JF - European polymer journal N2 - Elastomers are usually reinforced and employed in different applications. Various different nanoparticles, including layered silicates, carbon nanotubes, and expanded graphite, are currently being used as nanofiller. Multilayer Graphene (MLG) is proposed as promising nanofiller to improve the functional properties of Chlorine-Isobutylene-Isoprene Rubber (CIIR), Nitrile-Butadiene Rubber (NBR), Natural Rubber (NR) and Styrene–Butadiene Rubber (SBR) at low concentrations. MLG is constituted by only approximately 10 graphene sheets. Nanocomposites with extremely low MLG content (3 phr) showed evident improvement in rheological, mechanical and curing properties. The Young's modulus of the nanocomposites increased more than twice in comparison with the unfilled rubbers. MLG also improved the weathering resistance of the different rubbers. The nanocomposites conserved their initial mechanical properties against weathering exposure. KW - Elastomer KW - Nanocomposite KW - Multilayer graphene PY - 2015 DO - https://doi.org/10.1016/j.eurpolymj.2015.07.050 SN - 0014-3057 SN - 1873-1945 VL - 71 SP - 99 EP - 113 PB - Elsevier Ltd. CY - Oxford AN - OPUS4-33843 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wachtendorf, Volker A1 - Schulz, Ulrich A1 - Geburtig, Anja A1 - Stephan, Ina T1 - Mildew growth on automotive coatings influencing the results of outdoor weathering JF - Materials and corrosion N2 - As the results of a 14 weeks outdoor exposure of a series of automotive coatings in South Florida, the panels were found to be overgrown with an almost closed layer of mildew. Pinholes remained as permanent surface damage after removing the mildew mycelium. The extent of the damage differed in dependence of the kind of the coating. By tracing the images and profiles of the coating surfaces systematically over all phases of weathering and the subsequent cleaning procedure, a connection between formation of pinholes and mildew growth could be found. Outdoor weathering tests in other regions of Florida as well as in Europe and Australia showed that pinholes caused by mildew attack could also be found in all other locations, but always to a lower extent than in South Florida. The standardised mildew tests EN ISO 846 and MIL-STD 810F for laboratory exposure failed to reproduce the formation of pinholes. KW - Coatings KW - Mildew KW - Weathering KW - South Florida PY - 2012 DO - https://doi.org/10.1002/maco.201005784 SN - 0947-5117 SN - 1521-4176 VL - 63 IS - 2 SP - 140 EP - 147 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-25467 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Simone A1 - Wachtendorf, Volker A1 - Rauth, W. T1 - Kürzer in der Klimakammer - Rasche Beurteilung der Bewitterungsstabilität von 2K-PUR-Autolacken mittels Chemilumineszenz JF - Farbe und Lack KW - Weathering KW - Chemiluminescence KW - Degradation KW - Coatings PY - 2007 SN - 0014-7699 VL - 113 IS - 9 SP - 46 EP - 49 PB - Vincentz CY - Hannover AN - OPUS4-15786 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scholz, Philipp A1 - Falkenhagen, Jana A1 - Wachtendorf, Volker A1 - Brüll, Robert A1 - Simon, Franz-Georg T1 - Investigation on the Durability of a Polypropylene Geotextile under Artificial Aging Scenarios JF - Sustainability N2 - Geosynthetics are widely used in various civil engineering applications, such as geotextiles in coastal protection, and display a sustainable alternative to natural mineral materials. However, the full benefits of using geosynthetics can only be gained with a long service lifetime of the products. With the use of added stabilizers to the polymers, service lifetimes can be achieved in the range of 100 years. Therefore, accelerated aging methods are needed for the assessment of the long-term performance of geotextiles. In the present study, the behavior of geosynthetic materials made of polypropylene was investigated under artificial aging conditions involving elevated temperatures ranging from 30 to 80 °C, increased oxygen pressures ranging from 10 to 50 bar in water-filled autoclaves, and UV irradiation under atmospheric conditions. ATR-IR spectroscopy was employed to detect the increase in the carbonyl index over various aging durations, indicating the oxidative degradation of the geotextile. The most pronounced increase was observed in the case of aging through UV irradiation, followed by thermal aging. Elevated pressure, on the other hand, had a lower impact on oxidation. High-temperature size exclusion chromatography was utilized to follow the reduction in molar mass under different degradation conditions, and the results were consistent with those obtained from ATR-IR spectroscopy. In polyolefins such as polypropylene, Hindered Amine Stabilizers (HAS) are used to suppress oxidation caused by UV radiation. The quantitative analysis of HAS was carried out using a UV/Vis method and HPLC. The degradation of UV stabilizers during the aging of geotextiles is responsible for the oxidation and the reduction in the molar mass of polypropylene. From the results, it can be concluded that applications of PP geotextile without soil or sand cover might cause the risk of the formation of microplastic particles. Material selection, design, and maintenance of the construction must follow best practices, including the system’s removal or replacement at end-of-life. Otherwise, a sustainable use of geotextiles in civil engineering is not possible. KW - Geotextiles KW - Microplastic KW - Size exclusion chromatography KW - Accelerated aging PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599739 DO - https://doi.org/10.3390/su16093559 SN - 2071-1050 VL - 16 IS - 9 SP - 1 EP - 15 PB - MDPI AG CY - Basel AN - OPUS4-59973 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wachtendorf, Volker A1 - Kalbe, Ute A1 - Krüger, O. A1 - Bandow, Nicole ED - Brown, R. ED - Gedde, U.W. ED - Hedenqvist, M.S. T1 - Influence of weathering on the leaching behaviour of zinc and PAH from synthetic sports surfaces JF - Polymer Testing N2 - Synthetic materials used for outdoor sports grounds consist of a mix of inorganic, organic and polymeric compounds that show ageing due to weathering and a complex leaching behaviour by percolation of rainwater, which can limit its lifetime. Additionally, weathering exposure induces degradation processes in the polymers, which leads to the formation of new surfaces allowing water to access additional reservoirs of leachable compounds. A laboratory test comprising artificial weathering, ozonisation and subsequent leaching was developed to investigate this behaviour in a reproducible and controllable way. The experiments showed a general decline of Zn, polycyclic aromatic hydrocarbons (PAH) and total organic carbon (TOC) concentrations after an initial increase. Within this general trend, the course of concentration over exposure duration is very specific for individual sample materials and the analyte under investigation. The results indicate that weathering and degradation behaviour cannot be predicted from initial material conditions. Thus, weathering experiments are recommended to fill this gap of knowledge. KW - Athletic tracks KW - Artificial turf KW - Ageing KW - Artificial weathering KW - Polymer degradation KW - Rubber granules KW - Leaching KW - Contamination PY - 2017 DO - https://doi.org/10.1016/j.polymertesting.2017.09.021 SN - 0142-9418 SN - 1873-2348 VL - 63 IS - October SP - 621 EP - 631 PB - Elsevier Ltd. CY - Amsterdam, The Netherlands AN - OPUS4-42205 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Qiu, Y. A1 - Wachtendorf, Volker A1 - Klack, Patrick A1 - Qian, L. A1 - Liu, Z. A1 - Schartel, Bernhard T1 - Improved flame retardancy by synergy between cyclotetrasiloxane and phosphaphenanthrene/triazine compounds in epoxy thermoset JF - Polymer International N2 - A siloxane compound (MVC) and a bi-group phosphaphenanthrene/triazine compound (TGD) were employed in epoxy thermosets to explore high-efficiency flame retardant systems. With only 1wt% MVC and 3wt% TGD, an epoxy thermoset passed UL 94 V-0 rating test and achieved a limiting oxygen index value of 34.0%, exhibiting an excellent flame retardant effect. The MVC/TGD system not only decreased the peak value of heat release rate and effective heat of combustion but also imparted an improved charring ability to thermosets, thereby outstandingly reducing the flammability of 1%MVC/3%TGD/EP. Compared with the fire performance of 4%TGD/EP and 4%MVC/EP, the MVC/TGD system showed an obvious flame retardant synergistic effect, mainly depending on the general improvement of flame inhibition, charring and barrier effects of the thermoset during combustion. Evolved gas analysis combinedwith condensed-phase pyrolysis product Analysis jointly revealed the details of the changed pyrolysis mode. KW - Flame retardant KW - Epoxy resin KW - Synergy KW - Siloxane KW - DOPO KW - Triazine PY - 2017 DO - https://doi.org/10.1002/pi.5466 SN - 0959-8103 SN - 1097-0126 VL - 66 IS - 12 SP - 1883 EP - 1890 PB - Wiley AN - OPUS4-42950 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Niebergall, Ute A1 - Zanotto, M. A1 - Wachtendorf, Volker A1 - Böhning, Martin T1 - Impact of biodiesel sorption on tensile properties of PE-HD for container applications JF - Polymer Testing N2 - In previous papers, we investigated the influence of biodiesel or diesel on mechanical properties of a high-density polyethylene (PE-HD) for tank applications using Charpy impact tests and dynamicmechanical analysis (DMA). In this work, covering two more PE-HD materials, we extend our study to addressing the tensile properties, especially changes of Young's modulus, after immersion in biodiesel or diesel at 60 °C. As we cover sorption and desorption behavior, during desorption, i.e. storage at 60 °C in a circulating air oven, ageing or degradation phenomena were also observed and characterized in some detail using spectral reflectance measurements and FT-IR spectroscopy. The results obtained here support the concept of co-oxidation, i.e. the faster oxidation of the PE-HD matrix if the samples were previously saturated with biodiesel, itself easily oxidizable. KW - polyethylene KW - biodiesel KW - biofuels KW - sorption KW - plasticization KW - degradation PY - 2016 DO - https://doi.org/10.1016/j.polymertesting.2016.01.025 SN - 0142-9418 VL - 50 SP - 315 EP - 324 PB - Elsevier AN - OPUS4-35369 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -