Enhancement of the processibility of bismaleimide resins via copolymerisation with allyl organo-boron compounds

The main objective in modifying bismaleimide (BMI) is to improve its proces sibility and fracture toughness whilst retaining its heat resistance and go od hygrothermal stability. In this work, a new series of allyl compounds co ntaining boron (coded XB, XA, BQ), were prepared by esterification of allyl phenol compounds and boric acid. These structures were characterized by FT IR. The reactivity and curing behaviour of BMI resin systems modified by bo ron-containing compounds were investigated by gel time and differential sca nning calorimetry. The thermal stability and thermal mechanical properties of the cured copolymer were evaluated. No weight loss was observed when the copolymer was heated to 465 degrees C in a nitrogen atmosphere. The char y ields at 800 degrees C in nitrogen are more than 54%, the highest of them b eing 60%. The mechanical properties of the neat resin and glass-fibre-reinf orced composites are also discussed. (C) 1999 Published by Elsevier Science S.A. All rights reserved.