Kinetic analysis of the thermal degradation of PVC plastisols

The thermal degradation of plasticized polyvinyl chloride (plastisol) is reported here. Plastisols used in the present work were prepared with the plasticizer diethylhexyl phthalate in different proportions. Thermogravimetric analysis has been applied to study the behavior of plastisols at high temperatures and to evaluate their degradation kinetics. Several tests were carried out at different heating rates and the variation of the degree of reaction with time and temperature was calculated. The influence of the heating rate in dynamic measurements (5–40°C/min) on kinetic parameters, such as activation energies and reaction orders, has also been studied. These parameters were calculated from dynamic thermogravimetric analysis tests using Friedman analysis and a kinetic model for the degradation of poly(vinyl 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 degradation. The results of this study can be used to optimize the concentration of plasticizers and stabilizers in poly(vinyl chloride) formulations.