Dependence of the ultimate properties of a GR‐S rubber on strain rate and temperature

Abstract The tensile properties of an unfilled GR‐S rubber were measured with an Instron tensile tester at strain rates between 0.158 × 10 −3 and 0.158 sec. −1 and at fourteen temperatures between −67.8 and 93.3°C. The tensile strength and ultimate strain at the various strain rates and temperatures were superposed to give two composite curves which are functions of a reduced strain rate. From this superposition, the temperature dependence of the ultimate, properties was obtained. The temperature dependence between −53.8 and 71° is essentially the same as obtained by superposing the stress‐strain curves and is given by the Williams, Landel, and Ferry equation. From the composite curves and the temperature function, the tensile strength and the ultimate strain can be predicted at any strain rate and temperature, provided heating and wave propagation effects are negligible. The linear viscoelastic properties were obtained from the initial portions of stress‐strain curves and are represented by a reduced stress‐strain curve.