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

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 (fBNN-30/fBNNS, 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%, lambda value of the BNN-30@BNNS-III/E-44 composites was up to 0.61 W m-1K-1, increased by 2.8 times compared with pure E-44 (lambda = 0.22 W m(-1)K(-1)), also higher than that of the 15 wt% BNN-30/E-44 (0.56 W m-1K-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 lambda in-plane (lambda//) and lambda cross-plane (lambda(perpendicular to)) 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 (lambda// = 0.96 W m(-1)K(-1) and lambda(perpendicular to) = 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 x 10(14) Omega & 3.4 x 10(14) Omega center dot cm, favorable mechanical properties (flexural strength of 401.0 MPa and ILSS of 22.3 MPa), excellent dielectric properties (epsilon of 4.92 and tan delta of 0.008) and terrific thermal properties (T-g of 167.3 degrees C and T-HRI of 199.2 degrees C). (C) 2021 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.