TY - CONF A1 - von der Ehe, Kerstin A1 - Jaunich, Matthias A1 - Wolff, Dietmar A1 - Böhning, Martin A1 - Goering, Harald T1 - Radiation induced structural changes of (U)HMW polyethylene with regard to its application for radiation shielding N2 - The special properties of high molecular weight polyethylene (HMW-PE) and ultra high molecular weight polyethylene (UHMW-PE) result basically from their extreme chain lengths and their high degree of crystallinity. As high-performance polymers, they are used for a variety of applications. UHMW-PE in particular is often utilized for endoprothesis (due to its excellent slip and wear properties) and due to its high hydrogen content as a neutron moderator in casks for storage and transport of radioactive materials. To prepare the material for instance for its use as a total joint replacement, it is exposed to radiation for several reasons, such as sterilization and crosslinking, leading to partial improvement of the mechanical properties (e.g. fracture toughness, crack propagation resistance, wear resistance) and better chemical stability. To be applicable for long term radiation shielding purposes for instance over a period of 40 years, PE has to withstand any type of degradation affecting safety relevant aspects. The scope of our investigation comprises an estimation of the radiation impact on the molecular and supra molecular structure of two types of PE and to what extent these changes are detectable by thermo-analytical (TA) methods, such as Differential Scanning Calorimetry (DSC), Thermo Mechanical Analysis (TMA), Dynamic Mechanical Analysis (DMA) and Thermo Gravimetric Analysis (TGA). Additionally FT-IR spectroscopy as well as density and gas sorption measurements were carried out. Due to the poor solubility of HMW-PE and UHMW-PE, some classical analytical techniques are not applicable. But TA-methods represent a feasible approach to detect structural and morphological features of these materials as well as changes caused by external influences, such as thermal treatment and/or irradiation. With the combination of the applied TA-techniques it is possible to distinguish between crosslinking and degradation. T2 - PATRAM 2010 - 16th International symposium on the packaging and transport of radioactive materials CY - London, UK DA - 2010-10-03 PY - 2010 SP - 1 EP - 8 (T25/Paper 173) AN - OPUS4-24621 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - von der Ehe, Kerstin A1 - Jaunich, Matthias A1 - Böhning, Martin A1 - Goering, Harald A1 - Wolff, Dietmar T1 - Detection of structural changes of (U)HMW-PE induced by gamma irradiation T2 - 14th International conference "Polymeric materials" CY - Halle (Saale), Germany DA - 2010-09-15 PY - 2010 SN - 978-3-86829-282-4 SP - 1 EP - 6 PB - Druck-Zuck GmbH CY - Halle / Saale AN - OPUS4-21997 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wolff, Dietmar A1 - von der Ehe, Kerstin A1 - Jaunich, Matthias A1 - Böhning, Martin T1 - Performance of neutron radiation shielding material (U)HMW-PE influenced by gamma radiation T2 - PSAM 11 ESREL 2012 - 11th International probabilistic safety assessment and management conference & The annual european safety and reliability conference CY - Helsinki, Finland DA - 2012-06-25 KW - (U)HMW-PE KW - Gamma irradiation KW - Shielding material KW - Cask for storage and transport of radioactive materials PY - 2012 SP - 1 EP - 8(?) AN - OPUS4-26176 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Wolff, Dietmar A1 - von der Ehe, Kerstin A1 - Jaunich, Matthias A1 - Böhning, Martin A1 - Goering, Harald ED - Yamamoto, T. T1 - (U)HMWPE as neutron radiation shielding materials: impact of gamma radiation on structure and properties N2 - Due to their extreme high hydrogen contents, high molecular weight (HMW-) and ultra-high molecular weight (UHMW-) polyethylene (PE) are a comprehensible choice as neutron radiation shielding material in casks for storage and transport of radioactive materials. But as a direct consequence of inserting radioactive material in such casks, gamma radiation occurs. Hence, the impact of gamma radiation on the molecular structure of polyethylene has to be taken into consideration. Consequently, PE has to withstand any type of gamma radiation induced degradation affecting safety relevant aspects in order to be applicable for long term neutron radiation shielding purposes during the whole storage period (in Germany, for instance, up to 40 years). The scope of our investigation comprises an estimation of the impact of gamma radiation and temperature on the molecular and supra molecular structure of the two types of PE used as neutron radiation shielding cask components. A further point which is worth exploring is to what extent these changes are detectable by conventional analysis methods. Therefore, thermoanalytical measurements were performed such as differential scanning calorimetry (DSC), thermo mechanical analysis (TMA), dynamic mechanical analysis (DMA), and thermo gravimetric analysis (TGA). Additionally optical and weighing methods were applied. With those methods it is possible to detect structural changes in polyethylene induced by exposure to gamma radiation. The observed amounts of changes of the irradiated material are not safety relevant for the application of polyethylene as neutron radiation shielding material; moreover, some properties actually improve via irradiation. KW - HMW-PE KW - UHMW-PE KW - Gamma irradiation KW - Neutron radiation shielding material PY - 2013 SN - 978-0-8031-7533-4 U6 - https://doi.org/10.1520/STP103980 N1 - Serientitel: STP – Series title: STP VL - 25 IS - STP 1547 SP - 211 EP - 227 AN - OPUS4-27931 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jaunich, Matthias A1 - Böhning, Martin A1 - Braun, Ulrike A1 - Teteris, G. A1 - Stark, W. T1 - Investigation of the curing state of ethylene/vinyl acetate copolymer (EVA) for photovoltaic applications by gel content determination, rheology, DSC and FTIR N2 - The cure behaviour of a specific ethylene vinyl acetate material as used for encapsulation of photovoltaic modules was analysed by rheometer, differential scanning calorimetry and Fourier transform infrared spectroscopy to test for a suitable replacement for the laborious determination of gel content. The results show that all applied methods are capable of describing the effects of the cross-linking process. Some provide results very similar to those yielded by analysis of the insoluble content, but the question remains as to whether indirect methods should be preferred over the direct measurement of physical properties, e.g. as performed by the curemeter. A material stored for one year was also tested to demonstrate the effect of extended storage on cure behaviour and how this is detected by different methods. This complements the other methods, which were clearly able to detect the different cure behaviour of the aged EVA, whereas determination of the gel content could not. KW - Photovoltaic cell encapsulation KW - EVA KW - Incoming goods control KW - Insoluble content KW - Rheometer PY - 2016 U6 - https://doi.org/10.1016/j.polymertesting.2016.03.013 SN - 0142-9418 VL - 52 IS - 1 SP - 133 EP - 140 PB - Elsevier Ltd. CY - Oxford, UK AN - OPUS4-35918 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zaghdoudi, M. A1 - Kömmling, Anja A1 - Böhning, Martin A1 - Jaunich, Matthias T1 - Ageing of elastomers in air and in hydrogen environment: A comparative study N2 - EPDM, HNBR and FKM materials were exposed at 150 ◦C to air under atmospheric pressure and to hydrogen at 50 bar for different ageing times. All measurements after hydrogen exposure were conducted on samples in degassed condition to assess irreversible effects resulting from that exposure and to compare them to those after ageing in air. Density, hardness, tensile properties, compression set, and hydrogen permeability of all samples were analysed. In both ageing environments, HNBR exhibited the most significant changes of material properties. However, for both EPDM and HNBR, considerably less severe ageing effects were observed under hydrogen in comparison to ageing in air. On the other hand, FKM showed about the same low level of deterioration in both ageing environments but exhibited poor resistance against damage due to rapid gas decompression in hydrogen environment that can lead to seal failure. The obtained results may serve as a guidance toward a better understanding for design and utilisation of elastomeric materials in future hydrogen infrastructure components. KW - Rapid gas decompression KW - Condensed Matter Physics KW - Hydrogen KW - Sustainability and the Environment KW - Rubber sealing KW - Renewable Energy PY - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-597417 SN - 0360-3199 VL - 63 SP - 207 EP - 216 PB - Elsevier B.V. AN - OPUS4-59741 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -