The degradation of polyvinyl chloride in presence of phosphorus-containing plasticizers

Abstract

Abstract The introduction of plasticizers based on orthophosphoric acid esters into PVC significantly changes the thermal and thermo-oxidative degradation processes occuring in the polymer, consisting in HCl elimination, and formation of a conjugated double bond system and of statistical, isolated, C=C double bonds. Phosphate plasticizers intensify the thermal decay of PVC. The thermo-oxidative degradation may be retarded or on the other hand, substantially accelerated by phosphates. The process kinetics are determined by the nature and amount of plasticizer in the polymer composition and also by the decomposition products. As a result, the efficiency of metal-containing thermostabilizer-HCl acceptors and antioxidant-stabilizers is determined to an appreciable extent by the nature of the phosphate plasticizer being used.