Thermosetting bismaleimide resins generating covalent and multiple hydrogen bonds

摘要

Prepolymerizations of 4,4'-bismaleimidodiphenylmethane (BMI), diallyl isocyanurate (DAIC), and melamine (ML) at 160-170 degrees C and subsequent compression molding at 200-280 degrees C yielded cured BMI/DAIC/ML resins with feed molar ratios of 4/1/1, 3/1/1, and 2/1/1 (BMI-DAIC-ML411, 311, and 211). Similarly, cured BMI/DAIC 1/1 and BMI/ML 3/1 resins (BMI-DAIC11 and BMI-ML31) were prepared. The FT-IR analysis revealed that the maleimide and allyl groups were almost consumed for all the cured resins, and the hydrogen bonding interaction became stronger with decreasing BMI contents for BMI-DAIC-MLs. Based on the cured structures elucidated from the FT-IR result, the numbers of multiple hydrogen bonds and cross-linking covalent bonds (N-MHB and N-CB), and total cross-linking bond energy (E-TB) were evaluated to be 0, 7.92, and 618 for BMI-DAIC-ML411, 0.71, 7.81, and 627 for BMI-DAICML311, and 0.95 mol kg(-1), 7.61 mol kg(-1), and 617 kcal kg(-1) for BMI-DAIC-ML211, respectively. A higher order of glass transition and 5% weight loss temperatures for BMI-DAIC-MLs was 411> 311> 211 in accordance with a higher order of NCB. BMI-DAIC-MLs displayed a weak tan delta peak at 70-150 degrees C due to dissociation of the hydrogen bonds. The flexural strength and modulus of BMI-DAICML311 were higher than those of BMI-DAIC-ML411 in accordance with the difference of ETB. (c) 2015 Wiley Periodicals, Inc.