The thermal degradation of poly(vinyl acetate) and poly(ethylene- co-vinyl acetate), Part II: Modelling the degradation kinetics

Abstract

The thermal degradation kinetics of poly(vinyl acetate) (PVAc) and poly(ethylene- co-vinyl acetate) (EVA) copolymers in inert and oxidative conditions are modelled using a simplified mechanistic model. Experimental data originating from isothermal, constant heating rate and high resolution thermogravimetric analysis are used for rate parameter optimisation. The kinetics of the non-catalysed deacetylation reaction of the (co)polymers is studied for EVA with low weight percent vinyl acetate. These results are used to investigate the kinetics of the catalytic deacetylation and deactivation process of PVAc, EVA 73, and EVA 60. The rate parameters of the consecutive degradation of deacetylated PVAc and EVA by chain scission reactions (inert) or the charring and oxidation of char into CO 2 (oxidative) are optimised. The reaction mechanism with optimised rate parameters allows the description of the full degradation of PVAc and EVA over a large range of experimental conditions.