Mechanical and Thermal Properties of Bismaleimide Resins Modified with Oligo(imidothioether)s Having Terminal Maleimide Groups

Abstract

Mechanical and thermal properties of bismaleimide resins modified with maleimide-terminated oligo(imidothioether) s were evaluated. In chloroform, Michael addition reaction of trifunctional thiol to bismaleimide occurred in the presence of catalytic amount of triethylamine to give oligo(imidothioether)s having terminal maleimide groups. Adding the obtained oligomers to diallylbisphenol-A and bismaleimide resin led to improvement in the fracture toughness and the flexural strength of the cured resin without deterioration of the grass transition temperature and thermal decomposition temperature.The rate of relatively long crosslinking segment including the imidothioether structure to the other rigid structures in the cured resin increased via the oligomerization. Therefore, the oligo(imidothioether)-modified bismaleimide resins were softened and the fracture toughness and flexural strength were improved.