THE EFFECT OF TEMPERATURE ON CREEP AND PHYSICAL AGING OF POLY(VINYL CHLORIDE)

Tensile creep data have been obtained for poly(vinyl chloride) at a nu mber of temperatures ranging from 21.5 to 58 degrees C. The results we re obtained from specimens of different age characterized by the elaps ed time t(e) between quenching a sample from 85 degrees C to the test temperature and the start of the creep test. A model for interpreting non-linear creep data has been developed to describe the creep behavio ur of the material as a function of both age and temperature. The resu lts show that the effect of physical ageing is to progressively reduce the level of the relaxed beta compliance and to increase the mean ret ardation time of the glass-rubber alpha relaxation process. The effect of conducting creep tests on specimens of the same age at progressive ly higher temperatures is the opposite: the level of the relaxed beta compliance increases whilst the mean retardation times of the alpha pr ocess decrease. Neither the ageing rate nor the shape of the distribut ion of retardation times are affected by temperature.