CHARACTERIZATION OF POLYMERS UNDER LARGE DEFORMATION - 1. REPEATED CHEMICAL STRESS RELAXATION OF VULCANIZED RUBBERS.

In this investigation, repeated chemical stress relaxation measurements were carried out to observe the relaxation behaviour at large deformation. It was found that the repeated chemical stress relaxation curves were affected by both measurement temperature and the extension ratio of rubber. It was suggested on the basis of the results that temperature and mechanical stimulus have a similar effect on the stress relaxation curves. An equation is derived for the extension ratio and temperature and it is shown that the curves obtained by this equation were quite consistent with those obtained experimentally at different temperatures and extensions at large deformation.