Glass-transition temperature in the curing process of bismaleimide modified with diallylbisphenol A

The T_g-conversion relationship, during the thermal curing of different stoichiometric formulations of 1,1′-(methylene-di-4,1-phenylene) bismaleimide (BMI), modified with o,o′-diallyl bisphenol A (DABA), was investigated. The DiBenedetto equation was used to model this relationship for the formulation of DABA-1 (BMI:DABA, 1:1). Based on this model, the T_g-conversion relationship of formulation DABA-0.5 (BMI:DABA, 1:0.5) was modeled. The high consistency between the model curve and experimental data showed that the change of T_g, attributed to copolymerization between BMI and DABA in DABA-0.5, in the low-conversion regime, was the same as that in DABA-1. This also verifies that, for the formulation DABA-0.5, copolymerization and homopolymerization do not overlap with each other. The reactions progressed sequentially and homopolymerization occurred after completion of copolymerization. © 2004 Wiley Periodicals, Inc.