TY - JOUR A1 - Braun, Ulrike A1 - Wachtendorf, Volker A1 - Geburtig, Anja A1 - Bahr, Horst A1 - Schartel, Bernhard T1 - Weathering resistance of halogen-free flame retardance in thermoplastics JF - Polymer degradation and stability N2 - The influence of weathering on the fire retardancy of polymers is investigated by means of a cone calorimeter test, before and after artificial weathering. The surface degradation was monitored using different techniques (ATR–FTIR, microscopy, colour measurement). Different kinds of polymeric materials were chosen, all as they are used in practice: polycarbonate (PC) blends, polyamide (PA) and polypropylene (PP) flame-retarded with arylphosphate, melamine cyanurate (MC) and intumescent formulation based on ammonium polyphosphate (APP), respectively. All samples show material degradation at the surface due to weathering. No significant weathering influence occurs on the flame retardancy when it is a bulk property, as was observed for aryl phosphates in PC blends and MC in PA. When the fire retardancy is dominated by a surface mechanism, dependence on the duration of weathering is detected: for intumescent formulations based on ammonium APP in PP, a worsening in the formation of the intumescent network was observed. KW - Fire retardancy KW - Weathering resistance KW - Degradation KW - Intumescence KW - Cone calorimeter PY - 2010 DO - https://doi.org/10.1016/j.polymdegradstab.2010.08.020 SN - 0141-3910 SN - 1873-2321 VL - 95 IS - 12 SP - 2421 EP - 2429 PB - Applied Science Publ. CY - London AN - OPUS4-22612 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Simone A1 - Wachtendorf, Volker A1 - Rauth, W. A1 - Klimmasch, T. A1 - Krüger, P. T1 - Screening the weathering stability of automotive coatings by chemiluminescence JF - Journal of coatings technology and research N2 - Chemiluminescence (CL) is a sensitive method of investigating the thermo-oxidative stability of polymers in the early stages of degradation. Therefore, CL measurements were applied to different automotive coatings to evaluate their degradation behavior during artificial weathering. In this work, CL measurements were carried out for different automotive coatings to follow their degradation behavior during artificial weathering. The CL emission depends on sample-specific parameters like stabilizer, matrix, or hardener; experimental parameters like the oxygen partial pressure; and exposure parameters like the duration of weathering. The potential of CL could be demonstrated by classifying materials into categories of good, medium, and low degradation performance at a much earlier stage of weathering exposure than in combination with the usual visual detection of weathering effects. KW - Accelerated weathering KW - Coating KW - Chemiluminescence KW - Sensitive detection KW - Weathering PY - 2008 DO - https://doi.org/10.1007/s11998-007-9071-7 SN - 1547-0091 SN - 1935-3804 VL - 5 IS - 1 SP - 17 EP - 24 PB - Springer CY - Blue Bell, Pa. AN - OPUS4-16723 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rhiem, S. A1 - Barthel, Anne-Kathrin A1 - Meyer-Plath, A. A1 - Hennig, M. P. A1 - Wachtendorf, Volker A1 - Sturm, Heinz A1 - Schäffer, A. A1 - Maes, H. M. T1 - Release of 14C-labelled carbon nanotubes from polycarbonate composites JF - Environmental Pollution N2 - Waste disposal of carbon nanotube (CNT) containing products is expected to be the most important pathway for release of CNTs into the environment. In the present work, the use of radiolabelled CNTs (14C-CNT) for polycarbonate polymer nanocomposites with 1 wt% 14C-CNT content allowed for the first time to quantify and differentiate the CNT release according to the type of impact along the materials' ageing history. After an initial exposure of the nanocomposite by solar-like irradiation, further environmental impacts were applied to composite material. They aimed at mimicking disposal site conditions that may induce further ageing effects and CNT release. This study included shaking in water, rapid temperature changes, soaking in humic acid solution as well as waste water effluent, and, finally, gentle mechanical abrasion. All ageing impacts were applied sequentially, both on pristine (control) and on solar-irradiated nanocomposites. All experiments were accompanied by absolute quantification of radioactive release as well as chemical and morphological analyses of the nanocomposite surfaces using infra-red (IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The morphological analysis showed that spectral irradiation can uncover CNT networks on the outer nanocomposite surface layers by polymer degradation. After having subjected the solar-irradiated nanocomposite to all studied disposal site effect, the total radioactive release was quantified to amount to 64 mg CNT/m2, whereas only 0.8 mg CNT/m2 were found for the un-irradiated control sample. Solar degradation of polymers was thus found to significantly increase the propensity of the studied polymer nanocomposites to release CNTs during ageing effects at the product's end-of-life typical for disposal sites. KW - Weathering KW - Carbon nanotubes KW - Nanocomposites KW - Release KW - Quantification PY - 2016 UR - http://www.sciencedirect.com/science/article/pii/S0269749116303748 DO - https://doi.org/10.1016/j.envpol.2016.04.098 SN - 0269-7491 VL - 215 IS - August SP - 356 EP - 365 PB - Elsevier Ltd. CY - Paris AN - OPUS4-36899 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Trubiroha, Peter A1 - Geburtig, Anja A1 - Wachtendorf, Volker T1 - Referenzmaterialien für Bewitterungsprüfungen von polymeren Werkstoffen JF - Der Versuchs- und Forschungsingenieur KW - Referenzmaterial KW - Bestrahlen KW - Bewitterern KW - Polymer PY - 2003 SN - 0341-230X SN - 1431-827X VL - 36 IS - 3 SP - 35 EP - 39 PB - Baltz CY - München AN - OPUS4-2864 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fornacon-Wood, C. A1 - Stühler, M. R. A1 - Gallizioli, C. A1 - Manjunatha, B. R. A1 - Wachtendorf, Volker A1 - Schartel, Bernhard A1 - Plajer, A. J. T1 - Precise construction of weather-sensitive poly(ester-alt-thioesters) from phthalic thioanhydride and oxetane JF - Chemical Communications N2 - We report the selective ring opening copolymerisation (ROCOP) of oxetane and phthalic thioanhydride by a heterobimetallic Cr(III)K catalyst precisely yielding semi-crystalline alternating poly(esteralt- thioesters) which show improved degradability due to the thioester links in the polymer backbone. KW - Sulfur containing polymers KW - Durability KW - Weathering KW - Synthesis PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-590762 DO - https://doi.org/10.1039/d3cc03315e SN - 1364-548X VL - 59 IS - 76 SP - 11353 EP - 11356 PB - RSC AN - OPUS4-59076 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meyer, S. A1 - Timmel, S. A1 - Gläser, M. A1 - Braun, Ulrike A1 - Wachtendorf, Volker A1 - Hagendorf, C. T1 - Polymer foil additives trigger the formation of snail trails in photovoltaic modules JF - Solar energy materials & solar cells N2 - After several months of operation, many photovoltaic (PV) modules develop a discolouration defect called snail trails which appear as irregular dark traces across the cells. These traces are caused by silver nanoparticles accumulating within the encapsulation foil directly above the grid finger. In this work we systematically investigate combinations of encapsulation and back-sheet foils with respect to their susceptibility for snail trails. We can show that certain additive compositions within the encapsulation and back sheet foils are critical for the formation of the discolouring silver nanoparticles. We suggest a reaction model explaining the formation of snail trails from a chemical point of view. This fundamental understanding allows the rapid testing of foils for their snail trail sensitivity as well as the special design of resistant foils. KW - Snail trails KW - Encapsulation foil KW - Back-sheet foil KW - Additives KW - Silver nanoparticles PY - 2014 DO - https://doi.org/10.1016/j.solmat.2014.06.028 SN - 0927-0248 VL - 130 SP - 64 EP - 70 PB - Elsevier B.V. CY - Amsterdam [u.a.] AN - OPUS4-31249 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schartel, Bernhard A1 - Wachtendorf, Volker A1 - Hennecke, Manfred A1 - Grell, M. A1 - Bradley, D.D.C. T1 - Polarized fluorescence and orientational order parameters of a liquid-crystalline conjugated polymer JF - Physical review B N2 - We report a study of the orientational order of aligned thin films of the liquid crystalline conjugated polymer poly(9,9-dioctylfluorene). Steady state polarized fluorescence measurements were used to determine the orientational order parameter and . The influence of intermolecular and intramolecular excitation energy transfer on the degree of polarization is discussed. The role of film morphology is also examined by comparison of the results for glassy and crystalline films. KW - Liquid-cristalline conjugated Polymer KW - Polarized fluorescence measurements PY - 1999 SN - 1098-0121 SN - 0163-1829 SN - 0556-2805 SN - 1095-3795 SN - 1550-235X VL - 60 IS - 1 SP - 277 EP - 283 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-735 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schulz, Ulrich A1 - Wachtendorf, Volker A1 - Geburtig, Anja T1 - Pinholes - the negative impact of mildew growth JF - European coatings journal PY - 2004 SN - 0930-3847 VL - 5 SP - 26 EP - 30 PB - Vincentz CY - Hannover AN - OPUS4-21350 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Damerau, Thomas A1 - Sabelus, Silke A1 - Wachtendorf, Volker A1 - Hennecke, Manfred A1 - Greiner, A. T1 - Photochemische und thermische Stabilität eines Phenylen-Vinylen-Polymeren JF - GIT : Labor-Fachzeitschrift KW - Photostability KW - Fluorescence KW - Chemiluminescence PY - 1996 SN - 0016-3538 VL - 40 IS - 7 SP - 710 EP - 712 PB - GIT-Verlag CY - Darmstadt AN - OPUS4-23205 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Erdmann, Maren A1 - Kleinbub, Sherin A1 - Wachtendorf, Volker A1 - Schütter, Jan David A1 - Niebergall, Ute A1 - Böhning, Martin A1 - Koerdt, Andrea T1 - Photo-oxidation of PE-HD affecting polymer/fuel interaction and bacterial attachment JF - Materials Degradation N2 - In the present study, a simple approach was used to investigate the effect of UV-exposure on two high density Polyethylene materials (PE-HD), commonly used for storage tanks, on fuel sorption behavior and colonization by microorganisms. The aim was to investigate whether the sorption behavior of the fuels (diesel/biodiesel) and the colonization by microorganisms, frequently occurring in the fuel, is affected and may lead to undesirable or safety-relevant material changes. We showed that the UV-irradiation leads to significant changes of the sorption behavior due to chemi-crystallization and crosslinking. The fuel Sorption is affected by the UV-induced formation of polar carbonyl and hydroxyl groups predominantly occurring at the surface. With respect to microbial colonization behavior for Bacillus subtilis and Pseudomonas aeruginosa, isolated from a contaminated diesel sample, differences of the initial adhesion could be shown depending on the initial type of polyethylene as well as on the degree of UV-induced degradation. KW - High density polyethylene KW - Bacterial attachment KW - UV-irradiation KW - Fuel sorption PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510001 DO - https://doi.org/10.1038/s41529-020-0122-1 VL - 4 IS - 1 SP - Article number: 18 PB - Nature Partner Journals AN - OPUS4-51000 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -