Synthesis, characterization and microwave-enhanced polymerization of a phthalonitrile resin

A phthalonitrile terminated imide monomer was synthesized from 1,5-bis-[3,4-dicarboxyphenoxy] naphthalene dianhydride and 4-(3-aminophenoxy) phthalonitrile through thermal imidization process. This was characterized by FT-IR, 1H and 13C NMR spectral techniques. DSC studies were performed to follow the polymerization reaction. A three-step polymerization process was carried out with 5 wt% 4,4′-oxydianiline (ODA) curing agent under microwave irradiation. TGA analysis of cured resin showed excellent thermal properties at elevated temperatures with 61% char yield. The feasibility and benefit of using microwave radiation for the reaction will be discussed.