Abstract: Effect of nanoSiO2 content on the mechanical properties, thermal behavior and waterabsorbing of BMI/EP/DBA/nanoSiO2 composites was investigated. When the mass fraction of nanoSiO2 content was 2 %, the composites had higher strength and better toughness, compared with BMI/EP/DBA copolymers, and their tensile strength, flexural and notch impact strengths were improved by 22.8 %, 39.0 %, and 37.8 %, respectively. When the mass fraction of nanoSiO2 content was 2 %, the composites had excellent heat resistance; the glass transition temperature, initial degradation temperature, and the maximum degradation temperature were 204, 410, and 451 ℃, respectively.

Key words: bismaleimide resin, epoxy resin, nanosilicon dioxide, nanosilicon dioxide, thermal performance, mechanical property, waterabsorbing ability