The interactions between Poly(vinyl chloride) (PVC) and Plasticizers, responsible for polymer plasticization, can be detected by means of Fourier transform infrared spectroscopy (FTIR). The interaction capacity between the two components depends on plasticizer chemical nature, PVC stereoregularity, and plasticizer content. In the case of ternary systems, consisting in PVC and two different plasticizers, their interaction with PVC depends essentially on their chemical nature. In this work, FTIR spectroscopy is applied to determine the effect of the cited factors on the compatibility between plasticizer and resin. (C) 2007 Wiley Periodicals, Inc.