Enhanced properties of phthalonitrile resins under lower curing temperature via complex curing agent

Abstract

High curing temperature has been restricting the application and development of phthalonitrile resin. A complex curing agent containing melamine (ME) and ZnCl2 was developed to promote the curing reaction of resorcinol‐based phthalonitrile resin (DPPH). The thermal stability of ME can be significantly enhanced via adding ZnCl2, which was due to the interaction between ZnCl2 and amino group in ME. Moreover, the activities of pristine ZnCl2 and ME were improved via mixing, especially, the curing temperature for DPPH can be effectively reduced. Even at a curing temperature of 300°C, the 5% weight loss temperature of the resulting resin cured with complex curing agent still exceeded 500°C, which was much higher than those with pristine curing agents. In addition, the good long‐term oxidation stability and relatively low water absorption can also be obtained in the resins cured with novel curing agent. This work affords a facile route for designing high‐performance curing agent to improve the curing process of phthalonitrile resin.