COMPUTER-SIMULATION OF THE EFFECT OF STER EOISOMERISM ON THE THERMAL-DEGRADATION OF POLY(VINYL CHLORIDE)

Initial stages of the thermal degradation poly(vinyl chloride) were mo deled by the Monte-Carlo method. The effect of the polymer unit chain conformation on the cis-trans isomerism of an olefin formed by thermal elimination of HCl and on the length of kinetic degradation chain was considered, In the evaluation of the scale of influence of stereochem istry on the thermal degradation of PVC, the values of rate constants for the thermal degradation of meso-dyads were taken 10 to 100 times l arger than the corresponding rate constants for racemic dyads. The max imum calculated effect does not exceed 30%, whereas the stationary deg radation rates of real PVC samples differ at least 2 to 3 times, which is probably explained by the effect of structural defects on the degr adation rate.