Polyhydroxyurethane thermosets from novolac epoxide: Synthesis and its nanostructured blends with poly(trifluoroethylacrylate)-block-poly(N-vinylpyrrolidone) diblock copolymer

Abstract

A novel five-membered cyclic carbonate compound was synthesized via the reaction of novolac epoxide with carbon dioxide. The cyclic carbonate was then used as the precursor to prepare polyhydroxyurethane (PHU) thermosets with a trifunctional polyetheramine (i.e., Jeffamine T 403) as the crosslinking agent. To improve the thermomechanical properties as well as hydrophobicity, the PHU thermosets were further nanostructured by the use of a poly(trifluoroethyl acrylate)-block-poly(N-vinylpyrrolidinone) (PTFEA-b-PVPy) diblock copolymer. Compared to plain PHU thermoset, the nanostructured thermosets displayed enhanced glass transition temperatures (Tg's) and mechanical properties. Meanwhile, the surface hydrophobicity was significantly improved; the water surface contact angles of the thermosets have been increased up to 94.6°. With the introduction of PTFEA-b-PVPy, the nanostructured PHU thermosets still preserved the excellent shape memory and reprocessability at elevated temperature.