Thermal degradation of silane crosslinked unplasticized PVC

The thermal decomposition behaviour of rigid PVC, crosslinked using bis(gam ma -trimethoxysilylpropyl)amine as crosslinking agent has been studied. Dif ferent thermal stabilizers (tin and lead based) have been used with differe nt crosslinking agent concentrations, and the influence of these factors on the decomposition behaviour in inert atmosphere studied. Results obtained have shown that the main effect of aminosilane is an advance of the first s tage of the PVC degradation (i,e. the dehydrochlorination process). Moreove r, samples with different concentrations of silane, and at different stages of their processing (i.e. after milling, pressing, crosslinking) have also been used in order to elucidate the influence of these factors on their th ermal behaviour. A quantitative kinetic model has been developed and the co rresponding kinetic constants have been obtained by modelling the experimen tal thermogravimetric data. The kinetic parameters obtained have revealed a reduction in the apparent activation energy of the hydrogen chloride loss process, which has shown to be markedly dependent on the thermal stabilizer used. (C) 2001 Elsevier Science B.V. All rights reserved.