Research On Bismaleimide Molecular Composites

Based on the choice of rigid polymer, comonome(rRS)of BMI and ratio of RS/BMI, and preparation of rigid polymer/ (RS/BMI) resin system by Pre-in situ polymerization, this article researched the effect of molecular weight, content of PEI and initial-curing temperature on the reaction-induced decomposition in the curing course of PEI/ (RS/BMI) system, got the preparation conditions of BMI molecular composite,and researched the processing, toughness and practicability of BMI molecular composites.In formulation of resin, according to the correlation between reactivity, temperature sensitivity of reaction rate, processing of the resin and ratio of RS/BMI, we assured the optimal proportion of resins was RS/BMI=1:1(weight) in this paper. And by researching the gel and viscosity characteristics of resin system (RS/BMI=1:1), confirmed that the curing craft of resin was 160℃/2h+180℃/2h+200℃/3h+220℃/2h.It benefits generating of phase separation and improving of the rate of phase separation to the high content, molecular weight of PEI and initial-curing temperature. In this article, the preparation conditions of BMI molecular composite were that weight ratio of ODPA/DBPP was less than or equal to 0.700, content of PEI less than or equal to 5wt%, and initial-curing temperature less than or equal to 160℃. Combined with light transmittance, glass transition and scanning electron microscope (SEM) pictures of PEI/ (RS/BMI) system, it were found that PEI/ (RS/BMI) with 5wt%PEI was a homogeneous system which was called BMI molecular composite, when the ratio of ODPA/DBPP was 0.700 and initial-curing temperature 160℃.Comparing with RS/BMI resin system in this paper, BMI molecular composite had better toughness besides equivalent reactivity, processing property and heat resisting property. For instance, impact strength of BMI molecular composite was 115% higher than impact strength of RS/BMI resin system. When studied the effect of content of PEI on mechanical property for PEI/glass fiber/BMI hybrid composite, it was found that PEI/glass fiber/BMI hybrid composite with 5wt%PEI had highest mechanical property in this paper,So it decided the improving of mechanics properties of hybrid composite to high toughness and combination property of BMI molecular composite. BMI molecular composite had very good practicability.