OPTICALLY CLEAR SIMULTANEOUS INTERPENETRATING POLYMER NETWORKS BASED ON POLY(ETHYLENE GLYCOL)DIACRYLATE AND EPOXY .2. KINETIC-STUDY

Simultaneous interpenetrating polymer networks (SINs) based on diglyci dyl ether of bisphenol A (DGEBA) and poly(ethylene glycol) diacrylate (PEGDA) in weight ratios of 100/0, 50/50, and 0/ 100 were blended and cured simultaneously by using benzoyl peroxide (BPO) and m-xylenediami ne (MXDA) as curing agents. A kinetic study during SIN formation was c arried out at 45, 55, 63, and 70-degrees-C. Concentration changes for both the epoxide and C = C bond were monitored with FTIR. A rate expre ssion for DGEBA cure kinetics was established with a model reaction of phenyl glycidyl ether (PGE) and benzylamine. Experimental results rev ealed that lower rate constants and higher activation energy for the S IN were found, compared with those for the constituent DGEBA and PEGDA network formation. A model of network interlock was proposed to accou nt for this phenomenon. During simultaneous cure of DGEBA and PEGDA, t he interlock (mutual entanglement) between DGEBA and PEGDA networks pr ovided a sterically hindered environment, which subsequently increased the activation energy and reduced cure rates for both DGEBA and PEGDA . (C) 1993 John Wiley & Sons, Inc.