Synthesis, polymerization kinetics, and thermal properties of novel bismaleimides containing twisted structure

Abstract

AbstractIn this study, two types of ortho‐oxazine functionalized bismaleimides with exceptional thermal properties and solubility were synthesized. The excellent solubility in many solvents is attributed to the stable twisted structure of the monomer. The monomer containing the cyano group showed enhanced solubility. It was found that the curing mode of ortho‐oxazine functionalized bismaleimide was autocatalytically cured. In situ FT‐IR spectroscopic studies indicated that the structure of bismaleimide resin undergoes a structural transformation at higher temperatures to form benzoxazole resin with enhanced thermal stability. The carbon residue rates of bismaleimide and benzoxazole resins at 800°C were 69% and 77%, respectively. The new bismaleimide and benzoxazole resins were analyzed using Microscale Combustion Calorimeter (MCC), and it was found that they also possess excellent flame‐retardant properties, specifically benzoxazole resin.