New thermosetting resin from bisphenol A-based benzoxazine and bisoxazoline

Bisphenol A‐based benzoxazine was prepared from bisphenol A, formaline, and aniline. Curing reaction of bisphenol A‐based benzoxazine with bisoxazoline and the properties of the cured resin were investigated. Consequently, using triphenylphosphite as a catalyst, for the first time the ring‐opening reaction of benzoxazine ring occurred at 170°C, and then the phenolic hydroxyl group generated by the ring‐opening reaction of the benzoxazine ring reacted with the oxazoline ring at 200°C. The melt viscosity of the molding compound was kept 0.1–1 Pa · s at 140°C even after 1.5 h, and increased rapidly at 180°C. It was realized that the molding compound showed good flowability below 140°C, curing reaction proceeded above 180°C rapidly. The cured resin from bisphenol A‐based benzoxazine and bisoxazoline showed good heat resistance, water resistance, electrical insulation, and mechanical properties, compared with the cured resin from bisphenol A‐type novolac and bisoxazoline. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1551–1558, 1999