The role of dicumyl peroxide in the preparation of chloroprene rubber/starch/sodium acrylate water-swellable composites

Water-swellable composites were prepared by blending sodium acrylate (NaAA), additives, and chloroprene rubber (CR)/starch masterbatch which was pre-formed by latex compounding method. The effects of the content of dicumyl peroxide (DCP) on the properties of the composites were investigated. We found that an increase in DCP amount led to a large increase in water swelling ratio and meanwhile a decrease in the mass loss ratio. Further, the composites were swollen uniformly in water and thus kept their original shapes well. The hardness and stresses at 100% and 300% increased with the increase in DCP amount. The addition of DCP facilitated the homopolymerization of NaAA while decreased the esterification reaction between NaAA and CR, which was verified by vulcanization curves, DSC and FT-IR. The morphology of the composites before and after water immersion was observed by optical transmission microscopy and indicated that the starch was homogenously dispersed in the composites.