Preparation and properties of novel benzoxazine and polybenzoxazine with maleimide groups

Abstract

A benzoxazine compound with a maleimide group, 3-phenyl-3,4-dihydro-2H-6-(N-maleimido)-1,3-benzoxazine (HPM-Ba), was prepared from N-(4-hydroxyphenyl)maleimide, formaldehyde, and aniline. The chemical structure of HBM-Ba was identified by FT-IR, 1H-NMR, and elemental analysis. HPM-Ba showed a melting point of 52-55°C and good solubility in common organic solvents. HPM-Ba showed a two-stage process of thermal polymerization. The first stage arose from the polymerization of maleimide groups, and the second one was the ring-opening reaction of benzoxazine groups. Fusible polymaleimides with a Tg of around 100°C could be obtained by thermally polymerizing HPM-Ba at 130°C. Further polymerizing the polymaleimides at 240°C resulted in a completely cured resin showing a Tg at 204°C. Good thermal stability and self-extinguishing behavior was observed with the cured polybenzaxazine resins. © 2004 Wiley Periodicals, Inc.