Probability effect is one of the most important factors that influence the chemical reactions of polymers.A case in point is the dechlorination of polyvinyl chloride (PVC) when heated with zinc.Under the assumption that the probability of reaction of each adjacent pair of unreacted substituents is the same

Flory predicted that the theoretic value of the maximum extent of this reaction was86.47% (or1- e

-2

) via recursion method.In this article

under a different assumption that each unreacted substituent reacts with its adjacent substituent on either side with equal possibility

the reaction of one polymer chain was modeled by computer programming.The result indicated that the maximum extent of this reaction was86.06%. In the meanwhile

taking advantage of the fact that the instructions in the program were related to the intramolecular rotation of each freely rotating unit in the polymer chain

the procedure of this reaction was predicted and discussed and the kinetic plot which was in agreement with experiment result was obtained.