Carborane-containing bismaleimide resins with excellent heat resistance and dimensional stability

Novel carborane-containing bismaleimides with excellent heat resistance and dimensional stability for advanced composites are presented. First, a new kind of carborane-containing mono-maleimido-terminated monomer 1-(4-tolyl)-2-(4-maleimido phenyl)-o-carborane (CB-MI) was synthesized and characterized by FT-IR and ¹H-NMR. Then, it was used as a modifier for bismaleimide resin 4,4’-bismaleimidodiphenylmethane (BDM) with different weight fraction of CB-MI. The curing behavior and thermal property of the CB-MI/BDM resin systems were studied and presented here. Results displayed that a wide processing window and low curing temperature provided a good processability for the CB-MI/BDM resin system. Due to the effect of carborane groups, the char yield at 600°C of the cured resin systems tended to be increased with the addition of CB-MI. Moreover, the coefficient of thermal expansion of the resin was found to be reduced with the increase of CB-MI, indicative of a remarkable dimensional stability. This study might open up great opportunities for the preparation and design of various novel bismaleimides in a simple and feasible way and the resins with good thermal property and processability at the same time.