Composite number

Composite material

Epoxy

Materials science

Electrical conductor

Boron nitride

Journal of Material Science and Technology

• Hetero-structured BNN-30@BNNS thermally conductive fillers were successfully fabricated via electrostatic self-assembly method. • λ // and λ ┴ of BNN-30@BNNS-III (15wt%)/Si-GFs/E-44 composites reached 2.75 and 1.32 W m −1 K −1 , 186.5 % and 187.0 % higher than those of Si-GFs/E-44 composites. • Under the condition of point heat source by COMSOL software, the introduction of BNN-30@BNNS-III fillers were conducive to accelerating heat flow transfer. Hetero-structured thermally conductive spherical boron nitride and boron nitride nanosheets (BNN-30@BNNS) fillers were prepared via electrostatic self-assembly method. And the corresponding thermally conductive & electrically insulating BNN-30@BNNS/Si-GFs/E-44 laminated composites were then fabricated via hot compression. BNN-30@BNNS-III ( f BNN-30/ f BNNS, 1/2, wt/wt) fillers presented the optimal synergistic improvement effects on the thermal conductivities of epoxy composites. When the mass fraction of BNN-30@BNNS-III was 15 wt%, λ value of the BNN-30@BNNS-III/E-44 composites was up to 0.61 W m −1 K −1 , increased by 2.8 times compared with pure E-44 ( λ = 0.22 W m −1 K −1 ), also higher than that of the 15 wt% BNN-30/E-44 (0.56 W m −1 K −1 ), 15 wt% BNNS/E-44 (0.42 W m −1 K −1 ), and 15 wt% (BNN-30/BNNS)/E-44 (direct blending BNN-30/BNNS hybrid fillers, 1/2, wt/wt, 0.49 W m −1 K −1 ) composites. The λ in-plane ( λ // ) and λ cross-plane ( λ ┴ ) of 15 wt% BNN-30@BNNS-III/Si-GFs/E-44 laminated composites significantly reached 2.75 W m −1 K −1 and 1.32 W m −1 K −1 , 186.5 % and 187.0 % higher than those of Si-GFs/E-44 laminated composites ( λ // = 0.96 W m −1 K −1 and λ ┴ = 0.46 W m −1 K −1 ). Established models can well simulate heat transfer efficiency in the BNN-30@BNNS-III/Si-GFs/E-44 laminated composites. Under the condition of point heat source, the introduction of BNN-30@BNNS-III fillers were conducive to accelerating heat flow transfer. BNN-30@BNNS-III/Si-GFs/E-44 laminated composites also demonstrated outstanding electrical insulating properties (cross-plane withstanding voltage, breakdown strength, surface & volume resistivity of 51.3 kV, 23.8 kV mm −1 , 3.7 × 10 14 Ω & 3.4 × 10 14 Ω·cm, favorable mechanical properties (flexural strength of 401.0 MPa and ILSS of 22.3 MPa), excellent dielectric properties ( ε of 4.92 and tan δ of 0.008) and terrific thermal properties ( T g of 167.3 °C and T HRI of 199.2 °C).

Improvement of thermal conductivities and simulation model for glass fabrics reinforced epoxy laminated composites via introducing hetero-structured BNN-30@BNNS fillers