DECOMPOSITION OF VINYL ESTERS OF CYCLOALIPHATIC EPOXY RESINS: A KINETIC STUDY

Degradation behaviour of two methaacrylate terminated cycloaliphatic epoxy resins containing glycidyl epoxy group C₁E and epoxycyclohexane group C₂E were studied using thermogrametric analysis TGA techniques. The esters were cured by using styrene as diluent(40% w/w) and benzoyl peroxide as free radical indicator (2% w/w). The TG and DTG thermograms of both esters show single step degradation. The order of degradation reaction was found to be one for both esters. This was calculated using Coat and Redfern equation in accordance with best fit analysis and further confirm by linear regression analysis. From this value the activation energy and pre exponential factor was calculated. The study concluded that both vinyl esters have high thermal stability. Higher value of activation energy and frequency factor for ester C₂E shows that the ester is thermally more stable the ester C₁E, this is due to the presence of two cyclohexane ring in the resin C₁, increasing the number of cyclic rings within a cured epoxy resin structure generally leads to enhanced thermal stability.