A newly categorized in situ-polymerizing thermoplastic epoxy resin was developed. This resin can be easily impregnated into even fine gaps of continuous reinforcing fibers because of being a liquid mixture with low molecular weight in the initial state and can be allowed to linearly polymerize to become a very tough thermoplastic resin with no cross-links. Its polymerization proceeds by step-growth mechanism which is totally different from any other in situ-polymerizing thermoplastic resin. Therefore, the polymerization of thermoplastic epoxy resin can be stopped at any stage to be stored by cooling and restart to reach the final stage by heating again. That means the thermoplastic epoxy resin is stable in several stages from initial monomer mixture to fully extended polymer. In each stage, the rheological property of the resin drastically changes and different molding processes including not only infusion, RTM, stamping, roll forming, but also supersonic welding can be accordingly applied.
In Situ-polymerizing, Thermoplastic, Epoxy Resin, Step-growth Polymerization, Toughness, Molding Process