The customization of polymer networks can be made possible via dual-functional monomers, molecules characterized by two different reactive substituents that allow for versatile methods of polymerization. The dual-functional, epoxy-methacrylate monomers, glycidyl methacrylate (GMA), and vanillyl alcohol epoxy-methacrylate (VAEM), were polymerized with methyl methacrylate (MMA) via reversible addition-fragmentation chain transfer (RAFT) polymerization to form low molecular weight (~10–20 kDa) epoxy-functional thermoplastic copolymers, poly(VAEM-co-MMA), and poly(GMA-co-MMA). The copolymers were blended at 5 wt% into an epoxy resin system containing EPON Resin 828 and EPIKURE W Curing Agent and cured thermally to create unique interpenetrating polymer networks (IPNs). The resulting IPNs were compared to the cured neat resin and evaluated for thermal and mechanical properties, where maintained thermal properties and enhancements of stiffness and toughness were demonstrated.