CORRELATION BETWEEN INTRINSIC VISCOSITY AND TENSILE STRENGTH OF POLYPROPYLENE GEO-TEXTILES UNDER AGEING CONDITIONS

摘要

The reduction of tensile strength of polypropylene geo-textiles during photo-oxidation is mainly due to chain scission reactions, which results in a decrease of molecular weight of the polymer. Because the intrinsic viscosity of a polymer is an index of its molecular weight, it is therefore in this study to investigate the variation of the intrinsic viscosity of polypropylene filaments in order to seek the fundamental of the strength loss of the polypropylene filaments. Experiments are conducted to test the intrinsic viscosity of polypropylene filaments and also to record the strength loss of the corresponding specimens. Different UV ageing conditions are provided to test the specimens under the conditions of accelerated ageing and outdoor atmospheric ageing. According to the testing results of the intrinsic viscosity and tensile strength, a linear correlation could be established between these two data sets. However, the correlation varies under different ageing conditions. The FTIR tests are conducted to analyze the results under the two ageing experiments to explain the reasons leading to the difference.