Study On Bismaleimide Resin Modified With Carbon Nanotubes And Epoxy

Bismaleimide(BMI) resin is widely used in aeronautics, astronautics, mechanic and electronic industries because of its excellent thermal stability,electricproperties, radiation resistance, etc. However, the unmodified BMI have many weaknesses, such as high melting point, poor solubility,highbrittleness.In this paper,epoxy resin(EP) and multi-wall carbon nanotubes(MWNTs) were used to modify BMI in order to enhance its toughness. BMI had poor processing property, so BMI was copolymerized with diallyl bisphenol A(BA) to improve the processing property. The modification of this paper was based on the BMI/BA system.The surface treated MWNTs(MWNTs-COOH) were added into the BMI/BA system to prepare composites, the composites were cured at the process of 150?/1h+160?/1h+180?/2h+200?/2h. Results showed that the surfaces of MWNTs were grafted carboxyl group and the mass content of oxygen element was 5.94%. When the mass content of MWNTs-COOH was 1.5%, the impact strength of MWNTs-COOH/BMI/BA composites reached the highest value of 11.5 KJ/m2 which increased by 49.4% compared to BMI/BA system. At the same content of MWNTs-COOH, the heat resistance was the best, the thermal decomposition temperature was 411 oCwhich increased of 11 oCEpoxy resin was mixed with the BMI/BA system to prepare composites. Epoxy had good compatibility with BMI, so epoxy would copolymerize with BMI and they formed of interpenetrating networks structure. Results showed that the addition of epoxy decreased the heat resistance but increased the toughness of composites. When the mass content of epoxy was 10%, the impact strength went to maximum of 12.7 KJ/m2 increased by 64.9% than BMI/BA system.MWNTs and epoxy were both used to modified BMI to prepare MWNTs-COOH/(10%EP/BMI/BA) composites. When the mass content of MWNTs-COOH was 1.5%, the impact strength of composites reached the highest value of 16.2 KJ/m2 which increased 27.6% and 110.4% compared to EP/BMI/BAand BMI/BA composites, and the heat resistance was the best at the same time.Microspheres were prepared with method of micro emulsions, and microspheres were used to modify BMI/BA system. In the composites, microspheres were plastic point and could increase the toughness. Results showed that the microspheres were made and the mean diameter was 7~8 ?m. When the mass content of microspheres was 4%, the impact strength of composites was the maximum of 9.6 KJ/m2 increased by 24.7% compared to BMI/BA system.