Peroxide crosslinking of PVC foam formulations

Infrared and thermal analyses were used to evaluate the presence of residual unsaturation of a flexible foam formulation of PVC crosslinked by a peroxide/co-agent system. The crosslinking density of some samples was measured and compared with a sample crosslinked by triazine/MgO system in order to know more about the structure of the crosslinked network. Thermal stability of crosslinked samples was evaluated to compare both the crosslinking systems. Morphology of foamed and crosslinked samples was also investigated. Peroxide/TMPTMA appeared to be a reliable method of producing foamed and crosslinked plasticized PVC formulations; it allows the formation of a highly dense network, due to the trifunctional nature of the co-agent compared with the network formed with the triazine/MgO. The crosslinked samples by the peroxide/TMPTMA system did not show residual unsaturation after the optimum curing time.