RUBBER ELASTICITY AT LARGE DEFORMATION (VII)

Analysis of the Stress-strain Behaviors of Rubber Vulcanizates According to a Modified Mooney-Rivlin Equation

Abstract

A modified Mooney-Rivlin equation was obtained by replacing their strain function with the proposed one as
f=2(C₁^*+C₂^*/α)(α_m/2ln1+α/α_m/1-α/α_m-1/α²)
The modified Mooney-Rivlin equation was applied for the stress-strain curves of various kinds of rubber vulcanizates. As a result of the plotting, a good linear relationship was experimentally obtained. Among the parameters, that is, C₁, C₂, C₁^* and C₂^*, the following tendency was recognized with few exceptions.
i) C₁^*<C₁, ii) C₂^*>C₂, iii) C₁^*+C₂^*≥C₁+C₂
Comparing the modified Mooney-Rivlin equation with the proposed elastic equation, the following relations were obtained
νkT=2C₁^*
b=C₂^*(α_m/αln1+α/α_m/1-α/α_m-2/α³)
The proportionality between νkT and C₁^* was well recognized and the slope of a straight line had nearly a value of 2. On the other hand, the proportional correlation between b and C₂^* held only in the same kind of curing system