Abstract
The stress-strain curves of rubber vulcanizates such as NR, SBR, NBR and EPDM were measured under swelling condition, and these curves were analyzed according to our proposed rubber elastic equation and Mooney-Rivlin one, respectively.
It was found that parameters such as vkT, b, C1 and C2 obtained by the plots of both equations decreased with an increasing degree of swelling. The proportional relationships were obtained between vkT and C1, and b and C2, respectively. Equilibrium degree of crosslinking ve and non-equilibrium one vt are determined by swelling each sample in benzene, using the Flory-Rehner equation, to examine the relation between parameters and degree of crosslinking. Since b and C2 are proportional to (vt-ve), it is seemed that these parameters are concerned with pseudo-crosslinking. On the other hand, since vkT and C1 are proportional to vt, these parameters concern with not only primary linkage but also equilibrium pseudo-crosslinking which is not change under deformation.
