A theoretical study of the kinetics of loss of plasticizer from plasticized PVC foils

The kinetic model of the physical process of loss of plasticizer di-(2-ethylhexyl)-phthalate from plasticized poly(vinyl-chloride) foil was developed. The experimental investigations were carried out by the method of isothermal thermogravimetry in the temperature range of 120···150°C. The thickness of the foil was 0,1 mm and the amount of the plasticizer in the plasticized polymer was 10···40%. The kinetic parameters were estimated by the differential method of analysis. The rate of the process of weight loss of plasticizer from the foils can be described as the function of three variables, - dc/dt = f[T, c0, c(t)]. The value of the parameter n from the model - d(c0 - chl)/dt = f (T, c0) c0 - chl)n shows the linear dependence of the rate of evaporation on the residual concentration of plasticizer in the foil, and it also shows that the diffusion does not affect the process of plasticizer loss from plasticized polymer.