Effect of thermal annealing on plasticizer migration in Poly(vinyl chloride)/dioctyl phthalate system

Plasticizer migration studies dealing with poly(vinyl chloride) (PVC) sheets and liquid surrounding media revealed two parallel phenomena, migration of plasticizer and liquid penetration, that take place simultaneously. The present work was focused on correlating the structural differences of the PVC material with the aforementioned processes. The plasticizer and the liquid medium used were dioctyl phthalate and isopropanol, respectively. Emphasis was placed on any rearrangement of the polymer morphology occurring when elevated test temperatures were employed for a relatively long period of time (crystallization). The result was that the PVC structure seemed to become more compact, forcing the liquid medium that had already penetrated to come out. Furthermore, these experiments showed that plasticizer migration and liquid penetration were related to the polymer structure. (C) 2001 John Wiley & Sons, Inc.