The effect of temperature on creep and physical ageing of poly(vinyl chloride)

Abstract

Tensile creep data have been obtained for poly(vinyl chloride) at a number of temperatures ranging from 21.5 to 58°C. The results were obtained from specimens of different age characterized by the elapsed time t e between quenching a sample from 85°C to the test temperature and of the creep test. A model for interpreting non-linear creep data has been developed to describe the creep behaviour of the material as a function of both age and temperature. The results show that the effect of physical ageing is to progressively reduce the level of the relaxed β compliance and to increase the mean retardation time of the glass-rubber α relaxation process. The effect of conducting creep tests on specimens of the same age at progressively higher temperatures is the opposite: the level of the relaxed β compliance increases whilst the mean retardation times of the α process decrease. Neither the ageing rate nor the shape of the distribution of retardation times are affected by temperature.