Improvement of dielectric, processing and mechanical properties of phthalonitrile resins by copolymerisation with bismaleimide resin

Phthalonitrile resin is an excellent material with high-temperature resistance, making it an ideal choice for a variety of high-temperature applications. However, the rapid development of the electronics industry has resulted in the emergence of more rigorous performance requirements for high-temperature resistant materials. In this study, 4,4′-bismaleimidodiphenylmethane (BDM) was used to modify benzoxazine-containing phthalonitrile resin (BAph). The results demonstrated that the incorporation of BDM resin effectively reduces the curing reactivity of phthalonitrile (PN) resin and widens the processing temperature window. Moreover, the copolymer (Poly(PN-BDM)s) exhibits excellent dimensional and thermal stability, as well as a low dielectric constant, that are, CTE reduces from 134 ppm/°C of Poly(PN) to 94.1 ppm/°C of Poly(PN-40BDM), εr' decreases to 3.22. Furthermore, the excellent interfacial adhesion between the resin matrix composites (G(PN-BDM)s) resin and the glass fibers greatly improves the mechanical properties of the G(PN-BDM)s, with more than 3 times the peel strength and more than 2 times the flexural strength and modulus.