Fabrication of modified bismaleimide resins by hyperbranched phenyl polysiloxane and improvement of their thermal conductivities

Synthetic terminal amine group hyperbranched phenyl polysiloxane (NH₂-HBPSi) is introduced into a bismaleimide/diallylbisphenol A (BMI/DABA) prepolymer to fabricate NH₂-HBPSi/BMI/DABA resins. Furthermore, functionalized silicon carbide particle/silicon carbide whisker (fSiCp/fSiCw) hybrid fillers are also used to fabricate fSiCp/fSiCw/NH₂-HBPSi/BMI/DABA thermal conductivity composites. A NH₂-HBPSi/BMI/DABA resin with 20 wt% NH₂-HBPSi is an ideal dielectric material with excellent impact strength and outstanding thermal stability, the corresponding dielectric constant (ϵ) is 3.12, dielectric loss (tanδ) is 0.0098, impact strength value is 18.7 kJ m^-2, glass transition temperature (T_g) value is 281 °C and the 5 wt% thermal weight loss temperature (T₅) value is 424 °C. The thermal conductivities of the fSiCp/fSiCw/BMI/DABA and fSiCp/fSiCw/NH₂-HBPSi/BMI/DABA composites are both increased with the increasing mass fraction of fSiCp/fSiCw hybrid fillers.