Polyurethane acrylate/epoxy-amine acrylate hybrid polymer networks

New classes of hybrid polymer networks (HPNs), having variable polyurethane acrylate (PUA) and epoxy-amine acrylate (EAA) compositions, were prepared using initially miscible systems in methyl methacrylate (MMA). The initial systems were based on PUA prepolymer and EAA monomer solutions in MMA. HPNs were a result of epoxy-amine and radical polymerization competition. Phase separation occurred during the course of HPN formation. Mechanical dynamic analysis of the prepared HPNs showed good affinity between the PUA and PMM A phases and lower affinity between the EAA and PMMA phases. Mechanical pro perty evolution and transmission electronic microscopy showed that, for all the composition ranges used in this study (PUA/EAA/PMMA 15/45/40-45/15/40 wt %), the PUA-rich phase was the continuous phase. EAA-rich phases, 20-50 nm, in the PUA-rich matrix were obtained for HPNs containing up to 30 wt % EAA. For higher EAA concentration (45 wt %), 2 mu m EAA-rich phases were ob tained in the PUA-rich matrix. A substructure was also observed in each pha se. PUA/EAA copolymers were prepared and used successfully for the compatib ilization of the different phases of the HPNs. (C) 2000 John Wiley & Sons, Inc.