Characterization of thermal behavior of mixed bismaleimides for composites

摘要

Three types of bismaleimides viz., 4,4'-bismaleimido diphenyl methane (BDM), 4,4'-bismaleimidodiphenyl ether (BDE) and hexa-methylene bismaleimide (HMBI)were synthesized. The thermal behavior of these bis monomers inneat and blended forms was studied by thermoanalytical techniques.All the monomer systems undergo thermal polymerization after thecompletion of melting. An eutectic type single lowest meltingpoint is obtained for 60:40 limide formulations of BDM+HMBIand BDE+HMBI. The heat and kinetic parameters ofpolymerizaton are composition dependent and they show anincreasing trend with the increase of HMBI. The thermal stabilityand char content decrease with the increase of hexamethylenebidmaleimide whereas the thermal degradation kinetics show areverse trend. The flexural and shear storage modulus values of theglass composite laminates made with the bismaleimides are alsocomposition and temperature dependent.