TY - CONF A1 - Müller, Werner T1 - Long-term pull-out resistance and materials properties of geogrids T2 - 10th International Conference on Geosynthetics CY - Berlin, Germany DA - 2014-09-22 PY - 2014 AN - OPUS4-31590 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Werner T1 - On the determination of the chemical reduction factor for PET geogrids N2 - Data from four samples of commercially available PET geogrids (made either of yarns or bars), which were measured by BAM or other institute, are analyzed to discuss the procedure and problems of determining the chemical reduction factor RFCH associated with a certain service life. Estimates from Arrhenius extrapolation usually have very large statistical errors. The level of confidence must therefore be specified. A reliable estimate requires data from immersion tests below the glass transition temperature of PET. To extrapolate the time of reductions for each reduction factor at such low temperatures, one has to know the functional form of the mechanical degradation curve. It is shown how the degradation curve of the tensile strength may be obtained by determining the relation between increase in concentration of carboxyl end group (CEG) and decrease in tensile strength. Therefore, experimental studies to determine the chemical reduction factor should be accompanied by the measurements of the CEG concentration and the intrinsic viscosity. Furthermore, such measurements allow a non-ambiguous determination of the molecular mass. Hydrolytic molecular degradation will proceed continuously even at 20 °C with half-life of the inverse of the CEG concentration of 40–100 y. Nevertheless, small chemical reduction factors at a lifetime of 100 y are obtained with high level of confidence for materials with low initial CEG concentration and high molecular mass. This is shown by pooling data from samples with comparable CEG concentration, molecular mass and above all comparable intrinsic relation between increase in CEG concentration and decrease in strength. Therefore, the recommendation of ISO TR 20432, Table 2, for chemical reduction factors seems to be applicable to PET geogrids with index properties well below the one specified by the technical report. Whether these index properties are actually a sufficient condition to have small chemical reduction factors even at a very long service life is still an open question. The determination of chemical reduction factor should be based on aging experiments, at least for products with index properties close to the limiting values for the following reasons. (1) Even so standards are available, results of different laboratories on absolute values of CEG concentration and number averaged molecular mass differ to a certain extent. (2) Other factors, like crystallization, affect the mechanical degradation significantly. (3) There is no universally applicable form of the mechanical degradation curve. KW - Hydrolytic degradation KW - Polyester KW - Geogrid KW - Chemical reduction factor KW - Aging PY - 2014 DO - https://doi.org/10.1016/j.geotexmem.2013.12.009 SN - 0266-1144 VL - 42 IS - 2 SP - 98 EP - 110 PB - Elsevier CY - Amsterdam AN - OPUS4-30231 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pretsch, Thorsten A1 - Jakob, Ines A1 - Müller, Werner T1 - Hydrolytic degradation and functional stability of a segmented shape memory poly(ester urethane) N2 - In order to understand the effects of water and hydrolytic ageing on semi-crystalline poly(ester urethane) and its shape memory functionality, water immersion experiments at elevated temperature have been performed on a model substance and various parameters were monitored: change of the melting/crystallisation temperatures, substantial increase in crystallinity, temperature dependence of the water diffusion coefficient and solubility, hydrogen-bonding index and phase mixing by peak deconvolution of the FT-IR carbonyl region and day-to-day tensile and thermo-mechanical cyclic tensile tests. A rising fraction of freezable water agglomerates in the polymer was found for specimens cooled from the immersion temperature. The degradation process could be divided into three phases: an induction phase, a phase of continuous degradation and a phase of accelerated degradation. Shape recovery remains fairly constant during phase one and decreases slowly during phase two. The increase in crystallinity in phase two is accompanied by an increase in shape fixing ability. KW - Shape memory polymer KW - Poly(ester urethane) KW - Thermo-mechanical properties KW - Hydrolysis PY - 2009 DO - https://doi.org/10.1016/j.polymdegradstab.2008.10.012 SN - 0141-3910 SN - 1873-2321 VL - 94 IS - 1 SP - 61 EP - 73 PB - Applied Science Publ. CY - London AN - OPUS4-18661 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Werner T1 - Dichtungsbahnen zur Abdichtung von Deponien und Altlasten T2 - 25. Fachtagung "Die sichere Deponie", Süddeutsches Kunststoffzentrum (SKZ) CY - Würzburg, Germany DA - 2009-02-26 PY - 2009 AN - OPUS4-19015 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Werner A1 - Jakob, Ines A1 - Li, Chunshan A1 - Tatzky-Gerth, Renate T1 - Antioxidant depletion and OIT values of high impact PP strands KW - Polypropylene KW - Stabilizers KW - Oxidative resistance KW - Antioxidant depletion KW - Oxidative induction time PY - 2009 DO - https://doi.org/10.1142/S0256767909004102 SN - 0256-7679 VL - 27 IS - 3 SP - 435 EP - 445 PB - World Scientific CY - Singapore AN - OPUS4-19458 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, Werner ED - Egloffstein, T. T1 - Anforderungen an Kunststoff-Dränelemente für die langfristig sichere Entwässerung von Oberflächenabdichtungen T2 - 13. Karlsruher Deponie- und Altlastenseminar CY - Karlsruhe, Deutschland DA - 2003-09-17 KW - Geokunststoffe KW - Deponieabdichtungen KW - Beständigkeit PY - 2003 SN - 3-503-07485-6 SN - 0171-175X N1 - Serientitel: Abfallwirtschaft in Forschung und Praxis – Series title: Abfallwirtschaft in Forschung und Praxis IS - 128 SP - 107 EP - 118 PB - E. Schmidt CY - Berlin AN - OPUS4-2740 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Werner ED - Knipschild, F. T1 - Eignungsnachweis für Kunststoff-Dränelemente in Oberflächenabdichtungen T2 - 20. Fachtagung "Die sichere Deponie" CY - Würzburg, Deutschland DA - 2004-02-26 KW - Kunststoff-Dränelemente KW - Eignungsnachweis KW - Langzeitverhalten KW - Oberflächenabdichtungen PY - 2004 SP - G1 EP - G12 PB - SKZ CY - Würzburg AN - OPUS4-3221 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Müller, Werner A1 - Seeger, Stefan A1 - Thies, Martina A1 - Gerloff, Constantin ED - Floss, R. T1 - Long-Term Shear Strength of Multilayer Geosynthetics T2 - 3rd European Geosynthetics Conference "EuroGeo 3" - Geotechnical Engineering with Geosynthetics CY - Munich, Germany DA - 2004-03-01 PY - 2004 SN - 3-00-013305-4 VL - II SP - 429 EP - 434 PB - Deutsche Gesellschaft für Geotechnik CY - München AN - OPUS4-3326 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Werner ED - Jost, D. T1 - Eignungsgutachten für Kunststoff-Dränelemente durch die BAM T2 - 21. Fachtagung "Die sichere Deponie" CY - Würzburg, Deutschland DA - 2005-02-09 KW - Scherfestigkeit KW - Beständigkeit KW - Geokunststoffe KW - Prüftechnik PY - 2005 SP - C1 EP - C18 PB - SKZ CY - Würzburg AN - OPUS4-7027 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Seeger, Stefan A1 - Müller, Werner A1 - Jakob, Ines A1 - Tatzky-Gerth, Renate A1 - August, Hans T1 - Anforderungen an die Schutzschicht für die Dichtungsbahnen in der Kombinationsdichtung - Teil 1: Wirksamkeit (lastverteilende Wirkung und Beständigkeit), Materialien und Prüfverfahren bei Schutzschichten PY - 1995 SN - 0027-2957 SN - 1863-9763 VL - 27 IS - 8 SP - 544 EP - 560 PB - Erich Schmidt CY - Berlin AN - OPUS4-7589 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -