MORPHOLOGY OF ACRYLIC-EPOXY BICHAIN SIMULTANEOUS INTERPENETRATING POLYMER NETWORKS

Simultaneous interpenetrating polymer networks (SINs) were synthesized by two chain reactions of poly(n-butyl acrylate-co-ethyl dimethacrylate) (PnBA) and epoxy network. Degree of swelling, density, dynamic mechanical properties, and morphology of the SINs were measured. Theoretical analysis suggests a greater probability of interpenetration and entanglement between two networks for SINs from two chain reactions than for SINs from a chain reaction-step reaction combination. Comparison of the results of the glass-transition temperature of the bachain SINS with PNBA-epoxy SINs from the chain reaction-step reaction combination agrees with this conclusion. The PnBA-epoxy SINs are partially miscible systems. The presence of a third phase in a number of SINs is believed to represent the real interpenetration between two networks. Both composition and crosslinking density of PnBA affect the miscibility of SINs. The system is miscible at a supermolecular level for 2% cross-linked PnBA:epoxy = 10:90 SINs. The swelling property of SINs is affected by both phase continuity and interpenetration between two networks. The density measurements clearly show the presence of additional interactions. The interpenetration degree estimated from the density difference after the formation of SINs agrees with dynamic mechanical results. The transmission electron micrographs show a fine microstructure.