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(command-trimelhoxysilylpropyl)amine, a blend of trimethylol propane trimethacrylale and amorphous silica, and l,l-di-;-butylperoxy-3,3,5-trimethy] cyclohexane incorporating 40% peroxide. It was shown that rigid poly(vinyl chlorideJ can be crosslinked using both arninosilane and peroxide systems and the optimum level of the aminosilane was found to be ~2phr while significant property improvements were achieved with only 0-5 phr peroxide. The effects of the various thermal stabilisers and crosslinking additives arc presented and discussed.