Abstract
A semiempirical equation on the life time, tb of polymeric materials under tensile creep has been proposed. The present equation can be reduced to the Holland-Turner equation for low stress region (σ≤σC) and to the Zhurkov-Narsulaev equation for high stress region (σC<σ<σY), where σ, σC and σY are the applied stress, the characteristic stress, and the yield stress, respectively. As for the stress dependence of the life time, a good agreement was found between predicted behavior of this work and reported experimental results. The characteristic stress is affected by the factor such as the activation volume, the internal stress, σi and σY. The decrease of σC with increasing temperature arises from the decrease of σi and σY with temperature. It has been also shown that the temperature shift factor for reducing the plots of ln tb vs. ln σ to a master curve can be written as a function of the activation energy of σi and σY.
