Crosslinking of rigid poly(vinyl chloride)

Various formulations for the crosslinking of rigid poly(vinyl chloride) have been investigated including three different thermal stabilisers: a tin maleate; an octyl thio tin stabiliser; and a tribasic lead sulphate. The possibility of using aminosilanes and peroxides as crosslinking agents was considered and the additives used in the formulations were bis(-trimethoxysilylpropyl)amine, a blend of trimethylol propane trimethacrylate and amorphous silica, and 1,1-di-t-butylperoxy-3,3,5-trimethyl cyclohexane incorporating 40% peroxide. It was shown that rigid poly(vinyl chloride) can be crosslinked using both aminosilane and peroxide systems and the optimum level of the aminosilane was found to be 2 phr while significant property improvements were achieved with only 0·5 phr peroxide. The effects of the various thermal stabilisers and crosslinking additives are presented and discussed.