TY - JOUR A1 - Köth, A. A1 - Appelhans, Dietmar A1 - Robertson, Daniela A1 - Tiersch, B. A1 - Koetz, J. T1 - Use of weakly cationic dendritic glycopolymer for morphological transformation of phospholipid vesicles into tube-like networks N2 - Using cationic polyelectrolytes with different molecular architectures, only hyperbranched poly(ethyleneimine) with maltose shell is suited to tailor the morphological transformation of anionic vesicles into tube-like networks. The interaction features of those materials partly mimic biological features of tubular proteins in nature. KW - Cationic phospholipid vesicles KW - Anionic polyelectrolyte KW - Morphological transformatio PY - 2011 DO - https://doi.org/10.1039/c1sm06439h SN - 1744-683X VL - 7 SP - 10581 EP - 10584 PB - RSC Publ. CY - Cambridge AN - OPUS4-25070 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Robertson, Daniela T1 - The oxidative resistance of polymeric geosynthetic barriers (GBR-P) used for road and railway tunnels N2 - The results of autoclave tests according to DIN EN ISO 13438 (method C) and conventional oven tests in line with DIN EN 14575 are presented for the evaluation of the resistance to oxidation of geosynthetic barriers GBR-P based on polyethylene. These GBR-P products are used as a barrier layer against water in road and railway tunnels. The residual mechanical stability of the exposed materials was determined by tensile testing. The remaining activity of the stabiliser was investigated using the OIT method. The results of both accelerating test methods are discussed and compared in detail. Based on autoclave tests at three temperatures (e.g. 60, 70 and 80 °C) and 50 bar oxygen pressure, and additionally two more measurements at 80 °C and 10 and 20 bar oxygen pressure, a modified Arrhenius extrapolation is used for an assessment of the expected service time of one of the GBR-P products. KW - Geosynthetic barrier KW - Oxidative durability KW - Accelerated ageing KW - Autoclave KW - Oven PY - 2013 DO - https://doi.org/10.1016/j.polymertesting.2013.09.012 SN - 0142-9418 VL - 32 IS - 8 SP - 1594 EP - 1602 PB - Elsevier Science CY - Amsterdam [u.a.] AN - OPUS4-31442 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Robertson, Daniela T1 - Test method for testing oxidative resistance of polyethylene based products KW - Oxidation KW - Degradation KW - Polyethylene KW - Polypropylene PY - 2013 SN - 1042-7147 SN - 1099-1581 VL - 24 IS - Suppl. 1 SP - 1 PB - John Wiley & Sons, Ltd. CY - Chichester AN - OPUS4-29406 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Robertson, Daniela A1 - Kaundinya, I. ED - Ziegler, M. ED - Bräu, G. ED - Heerten, G. ED - Laackmann, K. T1 - Influence of transition metal ions on the thermo-oxidative degradation of polyethylene geomembranes (GBR-P) used in road tunnels N2 - Geomembranes are used to seal tunnels and similar constructions against mountain water insurgence. Such water contains different transition metal ions in the form of dissolved metal salts. The influence of metal ions on the oxidative degradation process of geomembranes based on polyethylene is examined. The tests were carried out with the autoclave method according to DIN EN ISO 13438, using a test media separately modified by different transition metal ions. Following the accelerated aging tests, tensile tests and FTIR analysis were carried out to assess the change in material properties during the treatment. Tensile strength and elongation at break for a defined failure criterion (e.g. T50, time to 50% drop of the residual tensile strength and strain relative to the initial value) are measured and the results show a decrease of T50 values during the aging with metal ions compared to the aged sample in the Standard test medium. FTIR results exhibited that a carbonyl peak in the region around 1700 to 1780 cm'1 arose during the thermal treatment, as a result of oxidative degradation. The carbonyl index of samples aged in different modified test media was monitored and the results showed metal ion specific differences in the ability to increase the carbonyl index. These results demonstrate that the presence of certain transition metal ions has a significant influence on the oxidative degradation process. The results presented in this paper are part of an R&D project [Report FE 15.461/2008/ERB, 2013] financed by the German Federal Highway Research Institute (BASt). T2 - 10th International conference on geosynthetics CY - Berlin, Germany DA - 21.09.2014 KW - Oxidation KW - Degradation KW - Transition metal ion KW - Acceleration KW - Very low density polyethylene (VLDPE) PY - 2014 SN - 978-3-9813953-9-6 SP - Paper 170, 1 EP - 7 AN - OPUS4-31716 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -