Kinetic aspects of aging of poly(vinyl chloride)-based polymer materials

The results of the complex study of samples of plasticized poly(vinyl chlor ide) (PVC) subjected to aging under model and climatic conditions or being in use for a long time (from 15 to 30 years at 253-301 K) studied by variou s techniques and the mechanism of their aging are presented in the article. Using the thermogravimetric, chromatographic, ultraviolet and infrared spe ctroscopic techniques, gel permeation chromatography, mercury porosimetry, and techniques for measuring mechanical strength properties of the material s (e.g., tensile strength and strain), we have shown that the service and f unctional properties of plasticized PVC were lost as a result of diffusion- controlled desorption of a plasticizer or other additives. Information abou t the aging conditions can be derived from the experimental time histories of the weight loss or additive depletion in the course of functioning of PV C samples or their exposure to different impacts. These experimental data a re used to formulate a mathematical description of the aging process in the se systems and to predict the lifetime of such materials in use. The experi mental part of the article is preceded with the literature review conveying the authors' point of view on the processes going on in PVC materials by a ging under the action of natural and artificial conditions.