Synthesis and Thermal Study of Cured Epoxy-Acrylate-Maleate, Unsaturated Polyester and Their Interpenetrating Networks of Varying Compositions

Epoxy-acrylate-maleate of bisphenol-C (ECAM), unsaturated polyester resin of phthalic anhydride, maleic anhydride and propylene glycol (PMP) were synthesized. ECAM, PMP and their varying compositions (25-75 wt%) were cured using MEKP and cobalt naphthenate and characterized by IR, DSC and TGA techniques. Interpenetrating networks possess intermediate thermal stability of ECAM (300 degrees C) and PMP (227 degrees C) and followed single step degradation with fractional order kinetics (0.6-2.4) leaving 10-25% residue above 400 degrees C. Low magnitudes of energy of activation and frequency factor of interpenetrating networks indicated improvement in flexibility due to toughening of PMP by ECAM of varying compositions.