Polycarbonate-hexagonal boron nitride composites with better dielectric properties for electronic applications

Hexagonal boron nitride (h-BN) reinforced polycarbonate (PC) composites were fabricated using solution method followed by hot pressing. The content of h-BN was varied from 0 to 60 wt% (similar to 44.4 vol%). The morphology, electrical volume resistivity, microhardness, and dielectric properties of the composites were characterized. Scanning electron microscopy showed uniform dispersion of h-BN particles in the PC matrix. X-ray diffraction and Fourier transforms infrared spectroscopy showed no change in morphology of PC present in the composites. The dielectric constant of the composites containing 60 wt% h-BN increased to 3.9. The dissipation factor of the composites reduced to less than 0.007 and the dispersion in dielectric constant of the composites became stable over the frequency from 1 kHz to 10 MHz compared to that of pure PC. The electrical volume resistivity of the composites remained close to that of pure PC. The microhardness increased approximately 25% at 50 wt% h-BN content and thereafter, a slight decrease in microhardness was observed.