MECHANICAL BEHAVIORS OF FULLY AND SEMIINTERPENETRATING POLYMER NETWORKS BASED ON EPOXY AND ACRYLICS

Fully interpenetrating polymer networks (fully IPNs) based on diglycid yl ether of bisphenol A (DGEBA) and ethylene dimethacrylate (EDMA) wer e prepared using isophronediamine and benzoyl peroxide as curing agent s. Semi-interpenetrating polymer networks (semi-IPNs) based on DGEBA a nd 2-hydroxyethyl methacrylate (HEMA) were also prepared using the sam e curing agents. The average activation energies of transition for bot h these IPNs were calculated from rheometric dynamic spectroscopy (r.d .s.) data, which indicated higher values for the fully IPNs than the c orresponding semi-IPNs. The more acrylic the interpenetrating polymer network (both fully and semi-IPNs) contained the lower the activation energy of transition. Broadened tan 6 peaks were observed for compatib le materials, implying an enhanced cracking energy absorption. RDS dat a also revealed a maximum half-width of tan 6 at 30% of EDMA for the f ully IPNs and at 25% of HEMA for the semi-IPNs. Beyond these compositi ons, decreased impact resistance and lower tensile modulus and elongat ion values were observed for these materials, presumably because of mi crophase-separation. Copyright (C) 1996 Elsevier Science Ltd.