Thermal conductivity and mechanical properties of BN-filled epoxy composite: effects of filler content, mixing conditions, and BN agglomerate size

Thermal conductivity and mechanical properties of boron nitride (BN)-filled epoxy composite as a function of filler content, mixing conditions, and BN agglomerate size were studied. Both thermal conductivity and mechanical properties of the composite were found to increase with increases in filler content, mixing speed, mixing time, and mixing temperature, but with decrease in BN agglomerate size. Sonication was found to be more effective in decreasing the BN agglomerate size than mechanical mixing. Viscosity of the BN-epoxy mixture was also studied under various mixing and sonicating conditions. A maximum thermal conductivity of 1.97 W/mK was obtained at 28 vol.% filler content and the mixing conditions of 80 rpm, 30 min, followed by sonication.