Structure-property relationships of irradiation crosslinked flexible PVC: Pt. 1

An investigation has been carried out into the effect of irradiation dose and the amount of the unsaturated monomer trimethylolpropane trimethacrylate (TMPTMA) on the irradiation of a di-iso-octyl phthalate (DIOP) plasticized PVC compound. The type of network structure produced and the extent of deterioration of the PVC after crosslinking have been studied. Within the dose range studied, the degradation caused by the electron beam was found to be minimal, but the residual unsaturation in the crosslinked PVC was significant, implying inefficient use of crosslinking agent. Gel yield increased with increased irradiation dose and TMPTMA content, but crosslink density decreased at higher irradiation levels, suggesting the formation of a looser network. The phthalate plasticizer was not involved in gel formation. (author)