Matrix resins based on bismaleimide–1,2‐polybutadienes

Improved thermally stable matrix resins have been obtained by the incorporation of 1,2‐polybutadiene in 4,4′‐bismaleimidodiphenylmethane. The thermal curing was performed at 185–195°C for 2.5 h and at 230–235°C for 45 min to give tough crosslinked polymers. The thermal curing reaction was monitered using FT‐IR and differential scanning calorimetry. Thermogravimetric analysis of the cured resins have shown improved thermal stability up to 490–480°C both in air and nitrogen atmospheres. The char yield obtained in nitrogen at 800°C was in the range of 50–49%. Graphite cloth laminates were prepared and tested. The laminates showed improved tensile strength over to parent bismaleimide. 1,2‐Polybutadiene was hydrogenated using 10% palladized‐charcoal. The resulting polymer was characterized by using IR and 1H‐NMR, which showed reduction of 15% pendent vinyl double bonds.