TY - JOUR A1 - Kömmling, Anja A1 - Chatzigiannakis, E. A1 - Beckmann, Jörg A1 - Wachtendorf, Volker A1 - von der Ehe, Kerstin A1 - Braun, Ulrike A1 - Jaunich, Matthias A1 - Schade, U. A1 - Wolff, Dietmar T1 - Discoloration Effects of High-Dose gamma-Irradiation and Long-Term Thermal Aging of (U) HMW-PE N2 - Two polyethylene types with ultra-high (UHMWPE) and high molecular weight (HMW-PE) used as neutron radiation shielding materials in casks for radioactive waste were irradiated with doses up to 600 kGy using a 60Co gammasource. Subsequently, thermal aging at 125∘C was applied for up to one year. Degradation effects in the materials were characterized using colorimetry, UV-Visspectroscopy, IR spectroscopy, and DSC. Both materials exhibited a yellowing upon irradiation.The discoloration of UHMW-PE disappeared again after thermal aging.Therefore, the yellowing is assumed to originate fromannealable color centers in the formof free radicals that are trapped in the crystalline regions of the polymer and recombine at elevated temperatures. For the antioxidantcontaining HMWPE, yellowing was observed after both irradiation and thermal aging. The color change was correlated mainly to decomposition products of the antioxidant in addition to trapped radicals as in UHMW-PE. Additionally, black spots appeared after thermal aging of HMW-PE. KW - Irradiation KW - UHMWPE KW - Colour center KW - Yellowness index PY - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-423992 SN - 1687-9422 VL - 2017 IS - Article ID 1362491 SP - 1 EP - 10 PB - Hindawi AN - OPUS4-42399 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -