Synthesis, curing and thermal properties of the low melting point phthalonitrile resins containing glycidyl groups

Two low melting point phthalonitrile monomers (EPN and EEPN) containing flexible glycidyl groups were synthesized using hydroxyl-containing phthalonitrile and epichlorohydrin as raw materials. The structures of the synthesized monomers were characterized by Fourier transform infrared (FT-IR), nuclear magnetic resonance ( 1 H-NMR and 13 C-NMR) spectra and elemental analysis. Then each of them was blended with 4-(4-aminophenoxy)-phthalonitrile (APPN) and cured to obtain two kinds of amine-catalytic phthalonitrile-based crosslinked polymers. DSC results showed that two blending systems underwent a two-stage polymerization process with the increase of curing temperature. Rheological measurements exhibited that the introduction of glycidyl groups to phthalonitrile resin could greatly improve its processability. Moreover, after thermal cured at 300 ℃, the resulting phthalonitrile resins exhibited excellent mechanical performance, thermal and thermo-oxidative stability.