Kinetics of decomposition of poly(vinyl chloride)/low-migration polyesterurethane plasticizer blend - a thermogravimetric study

Abstract

Kinetics of decomposition of poly(vinyl chloride) (PVC), plasticized either by di(2-ethylhexyl)phthalate (DEHP) or medium molecular weight polyesterurethane (PESTUR) or by both plasticizers, was studied by isoconversionalmethods on the basis of thermogravimetric data under dynamic heating conditions. It has been found that the initial decomposition temperature is higher for PVC plasticized with PESTUR in comparison with PVC plasticized with DEHP or with PESTUR/DEHP, and thermal degradation shows features of multistep complex process. Application of polymeric plasticizer leads to the increase in values and a smoothing effect in the course of energy of activation and pre-exponential factor at initial stage of decomposition indicating thus the hindered migration of medium molecular weight compound from PVC matrix (in comparison with PVC containing monomeric DEHP) due to steric hindrances as well as due to specific interactions between C=O and Cl groups along the macrochains.