Functionalized glass fibers cloth/spherical BN fillers/epoxy laminated composites with excellent thermal conductivities and electrical insulation properties

Thermally conducive glass fibers cloth/spherical boron nitride fillers/epoxy (GFs/BN/epoxy) laminated cornposites with excellent electrical insulation properties were fabricated by blending-impregnation followed by hot compression method. Epichlorohydrin (ECH) was successfully grafted onto the surface of GFs (f-GFs), in favor of improving the mechanical properties of the f-GFs/epoxy laminated composites. For a given spherical BN fillers loading, GBN-100 with relatively larger particle size was more benefit for enhancing the thermal conductivities of the BN/epoxy composites. Meantime, thermal conductivity coefficient (lambda) values of the f-GB/GBN-100/epoxy laminated composites were gradually enhanced with the increasing addition of GBN-100 fillers. When the mass fraction of GBN-100 fillers was 20 wt%, the lambda in vertical (lambda(perpendicular to)) and parallel (lambda(parallel to)) of the f-GB/GBN-100/epoxy laminated composites was the maximum of 1.21 and 3.55 W m(-1) K-1, about 3 and 6 times than that of thef-GFs/epoxy laminated composites (lambda(perpendicular to) of 0.41 W m(-1) K-1 and lambda(parallel to) of 0.66 W m(-1) K-1), respectively, and much higher than that of pure epoxy matrix (0.23 W m(-1) K-1). Meantime, the surface resistivity and breakdown strength of the f-GB/GBN-100/epoxy laminated composites with 20 wt% GBN-100 fillers was respectively decreased to 5.1*10(14) Omega and 7 KV mm(-1), but still maintained excellent electrical insulation properties.