CREEP AND PHYSICAL AGING OF PVC - DEPENDENCE ON STRESS AND TEMPERATURE

On the basis of new data obtained for PVC, extensions have been made t o the authors' model for analysing the creep compliance curves of glas sy, amorphous polymers. Short-term data in the a-region have been fitt ed with a stretched exponential function containing an effective retar dation time, t(0), which increases with the age of the polymer and dec reases with stress and temperature. Physical aging during long-term cr eep gives rise to an increase in t(0) with creep time, the rate of inc rease depending on stress and temperature. Functions have been develop ed which quantitatively describe these variations in t(0), and which r elate the creep compliance to age-state, creep time, stress and temper ature. These functions could provide a basis for predicting the creep behaviour over wide and continuous ranges of test variables from data acquired in a limited number of tests.