Curing and decomposition behaviour of vinyl ester resins in presence of methyl methacrylate

Vinyl ester resins V1, V2 and V3 of acid value (͠ 5 mg KOH/g solid) were synthesized using bisphenol-A epoxy and acrylic acid in presence of triethyl- tripropyl- and tributyl-, amines, respectively. The synthesized resins were characterized by FTIR spectroscopy and amines were found to be attached to the resin structure by a hydrogen bond. The curing behaviour of synthesized resin containing 40 % methyl methacrylate (w/w) and 2 % benzoyl peroxide was studied using DSC and found to be affected by the presence of amines. Amines played dual role during the curing, it acted as an accelerator as well as chain transfer agent. The kinetic parameters for the curing reactions were determined using Ozawa's method. The energy of activation and frequency factor for V1 to V3 increases from 16 - 21 kcal mol-1 and 2.16 x 109- 5.01 x 1011 min-1, respectively. The curing reactions followed first order kinetics and obeyed the Arrhenius rate expression. The decomposition behaviour of all the samples were studied using TGA at 10°C min -1. The TG and DTG thermograms show single step degradation. The energy of activation and frequency factor for the degradation were determined using Coats and Redfern method.