The effect of a low‐viscosity swelling liquid on the tensile strength of rubber

The paper examines the effect of swelling on a number of different gum rubbers and rubbers filled with different types and concentrations of black. The observed decrease in strength with decreasing rubber fraction V r (increasing swelling ratio) is, in the case of gum rubbers, associated with a decrease in internal friction. The incorporation of a black filler is shown to increase strength by hydrodynamic stiffening and by an increase in internal friction of the rubber network, and a simple reduction scheme of the data shows a close analogy between the strength as a function of V r and the dynamic modulus of a rubber solution as a function of concentration. The results lead to a failure criterion, which describes the energy density at break as a simple function of the hysteresis near break.