VULCANIZATION TIME WITH PEROXIDE CURE SYSTEMS.

Natural rubber can be vulcanized with organic peroxides, typically dicumyl peroxide (DCP), to achieve good aging resistance and excellent resistance to compression set at high temperatures (70-100 degree C). To obtain the best compression set performance, freedom from certain other compounding ingredients, especially zinc oxide and stearic acid, is essential. Although they scorch rather easily, dicumyl peroxide mixes are not very fast curing and even at 160 degree C complete peroxide decomposition, and hence maximum vulcanizate modulus, is only attained after some 60 minutes. This paper discusses the peroxide curing mechanism with emphasis on the decomposition of DCP in natural rubber. Some experimental data are tabulated, plotted and evaluated.