KINETIC-STUDIES OF COMPATIBLE SIMULTANEOUS INTERPENETRATING POLYMER NETWORKS BASED ON POLY(POLY(ETHYLENE GLYCOL) MALEATE) AND EPOXY-RESIN

A simultaneous interpenetrating polymer network (SIN) based on diglycidyl ether of bisphenol A (DGEBA) and poly(poly(ethylene glycol) maleate) (PPEGMA) in a 50/50 weight ratio was blended and was cured simultaneously by using benzoyl peroxide and m-xylenediamine as curing agents. Kinetic studies during SIN formation were carried out at 50, 60, 65 and 70-degree-C. Concentration changes of both epoxide and double bonds were monitored with Fourier-transform infra-red spectroscopy. Rate expressions were established with model reactions. Experimental results revealed that lower rate constants and higher activation energies for SIN were found compared with those for the formation of the respective component networks. A network interlock effect was proposed to account for this phenomenon. During simultaneous cure of DGEBA and PPEGMA, network interlock must provide a sterically hindered environment, which subsequently increased activation energies and reduced cure rates for both DGEBA and PPEGMA.