Kinetic analysis of the thermal degradation of PVC plastisols

The thermal degradation of plasticized polyvinyl chloride (plastisol) is re ported here. Plastisols used in the present work were prepared with the pla sticizer diethylhexyl phthalate in different proportions. Thermogravimetric analysis has been applied to study the behavior of plastisols at high temp eratures and to evaluate their degradation kinetics. Several tests were car ried out at different heating rates and the variation of the degree of reac tion with time and temperature was calculated. The influence of the heating rate in dynamic measurements (5-40 degrees C/min) on kinetic parameters, s uch as activation energies and reaction orders, has also been studied. Thes e parameters were calculated from dynamic thermogravimetric analysis tests using Friedman analysis and a kinetic model for the degradation of poly(vin yl chloride) and plastisols has been then developed. The obtained model was able to simulate the thermal degradation process of plastisols in dynamic conditions and was used to evaluate the effects of additives in the degrada tion. The results of this study can be used to optimize the concentration o f plasticizers and stabilizers in poly(vinyl chloride) formulations. (C) 19 99 John Wiley & Sons, Inc.