Synthesis and Characterization of Pyrimidine-Based Novel Phthalonitrile Resins with Excellent Processing Performance and High Glass Transition Temperature

Three phthalonitrile monomers containing pyrimidine ring and benzene ring side group were successfully synthesized with 4, 6-dichloro-2-phenylpyrimidine, three kinds of phenols (resorcinol, bisphenol A and bisphenol AF) and 4-nitrophthalonitrile via nucleophilic substitution reaction. All the phthalonitrile monomers exhibited excellent processing performance due to low melting points (T-m) (below 100 degrees C) and wide processing windows (difference between melting temperature and curing temperature) above 140 degrees C. By introducing pyrimidine ring and benzene ring side group, the lower melting point of monomers did not affect the thermal stability and thermal mechanical properties of the phthalonitrile resins based on different bisphenols. In particular, 5 % thermal decomposition temperature (T-5%) and glass transition temperature (T-g) of phthalonitrile resin based on resorcinol surpassed 455 and 400 degrees C while storage modulus (E ') was 3209 MPa. Therefore, phthalonitrile resin containing pyrimidine ring and benzene ring side group have potential applications in the field of high temperature resistant polymers and composites.