A Note on Stress Relaxation of Rubber Networks in the Vicinity of Room Temperature

Abstract

Abstract The question of whether stress relaxation of natural rubber under normal usage at room temperature up to 100° C is caused primarily by chemical aging or physical phenomena connected with reversible changes is one which has been extensively studied. Thirion and Chasset investigated the relative effects of network relaxation and aging for dicumyl peroxide cured natural rubber in air and found network relaxation effects predominating below 55° C with aging becoming increasingly important at higher temperatures and longer times. In this study samples of natural rubber, cured by dicumyl peroxide, were relaxed both in air and in vacuum in an attempt to elucidate further the phenomenon of network relaxation. It was concluded that stress relaxation between 25° C and 100° C is much smaller in vacuum than in air, and that true equilibrium stresses are rapidly reached in vacuum.