Styrene-butadiene rubber/epoxidized natural rubber blends: The effect of vulcanization system on blends properties

The dynamic properties, curing characteristics, and swelling behavior of the blends cured using two types: nf vulcanization systems [i.e., conventional vulcanization (CV) and semiefficient vulcanization (semi-EV)] were investigated. Results indicate that the maximum elastic torque (S' @MH) and the torque difference, S'@MH-S'@ML (maximum elastic torque minus minimum elastic torque) increased with the increasing epoxidized natural rubber (ENR) composition in the blend. However, a reverse trend was observed for tan delta @MH and viscous torque (S " @MH). At a similar blend ratio, the CV system gives a higher S' @MH and torque difference but a lower tan delta @MH and S " @MH than the semi-EV system. The scorch time, t(2) and cure time, t(90), decreased with increasing ENR composition in the blends. Semi-EV system blends exhibit shorter t(2) and t(90) than CV system blends. The swelling degree decreased with increasing ENR composition in the blends and the CV system blends show better oil-swelling resistance.