A modification of the method of intermittent stress relaxation measurements on rubber vulcanizates

Abstract

AbstractThe method of continuous and intermittent stress relaxation measurements on rubber vulcanizates developed by Tobolsky and co‐workers has been modified by the introduction of intermittent tangent modulus measurements during the continuous relaxation experiments. This allows rate of scission and crosslinking to be determined simultaneously and on the same specimen. The method is based on the use of small or moderate extension ratios α and on the fact that in this case the stress f in actual rubbers is represented more closely by the empirical relationship f = 3G(1−1/α) than by the theoretical f = G[α−(1/α2)], where 3G denotes Young's modulus at infinitesimally small strains.