TY - JOUR A1 - Müller, Werner A1 - Büttgenbach, Beate A1 - Jakob, Ines A1 - Mann, Heidemarie T1 - Comparison of the oxidative resistance of various polyolefin geotextiles JF - Geotextiles and Geomembranes N2 - Data are reported from oven aging in circulating air and water immersion tests at 80°C on various polyolefin (polyethylene (PE) and polypropylene (PP)) needle-punched nonwoven geotextiles (GTnws) and the results of these long-term tests are compared with the oxidative resistance of high-density PE geomembranes (HDPE GMs) described in a preceding paper (Polym. Degr. Stability 79(1) (2003) 161). Polyolefin fibers used in geotextiles are typically less stabilized, have a very high surface-to-volume ratio and an oriented morphology compared with HDPE GMs. Therefore, significant differences in the oxidation behavior of these products are expected which may affect their durability. Two general results can be obtained from our measurements: Firstly, while the lifetime of the HDPE GM is essentially determined by the slow loss of stabilizers, for all GTnws a rapid reduction in the oxidative induction time (OIT) and, as we conclude, in the amount of stabilizer was observed during water immersion and air aging. Secondly, the mechanical property degradation of the GTnws depended strongly on the oxidation conditions: the induction period prior to the degradation was much longer for immersion in water than for oven aging in circulating air. After antioxidant depletion, an induction time of the oxidation reaction, which depends on the draw ratio of the stretched fibers and the oxygen supply, might substantially contribute to the induction period of the mechanical property degradation of GTnws. For one PP GTnw product, a sudden reduction in the mechanical strength occurred after onset of degradation which continued rapidly until complete deterioration. For other PP samples as well as for all PE GTnws the reduction in mechanical strength proceeded slowly. Best fits were obtained by modeling the degradation process of the PE GTnws by a second-order kinetic. Using an activation energy of 60 kJ/mol (Geotextiles, Geomembranes and Related Products, Balkema, Rotterdam, 1990; Conference Proceedings of the Sixth International Conference on Geosynthetics, Industrial Fabrics Association International (IFAI), Atlanta, USA, 1998, pp. 683–690; Clay Geosynthetic Barriers, Balkema, Lisse, The Netherlands, 2002, pp. 87–96), lower limits of the half-live of the degradation at worst case field conditions were obtained in the range 30–83 years. Some decades have to be added for the overall induction time. However, under field conditions with limited oxygen supply, the expected service lifetime might be at least half an order of magnitude longer. KW - Durability KW - Geotextile KW - Oxidative resistance KW - Test methods KW - Long-term testing PY - 2003 DO - https://doi.org/10.1016/S0266-1144(03)00032-3 SN - 0266-1144 VL - 21 SP - 289 EP - 315 PB - Elsevier CY - Amsterdam AN - OPUS4-2632 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -