Thermal and Dielectric Characteristics of Aluminum Nitride/HTV Silicone Composites

Abstract

The study describes the use of nano aluminum nitride in developing thermally conductive and electrically insulating materials. An experimental approach is followed, starting with the hydrophobic surface treatment of nanofillers using HMDS. TEM and XRD analysis are used to confirm the nanofiller presence and gain insight regarding the filler shape, dimensions, and phase. EDX, FTIR and XRD analysis revealed the co-existence of aluminum oxide in traces along with aluminum nitride. XRD patterns revealed no change after surface modification and confirmed the presence of an amorphous functionalized layer. The protocol for composite compounding is described in detail. SEM analysis of composites revealed a moderate degree of dispersion with localized pockets of agglomeration. Further, the TEM analysis performed gave insight into the dispersion of nanofillers. Finally, DSC analysis is performed to understand the effects of nano aluminum nitride on glass transition, melting point, and crystallization temperatures. An interesting pattern of increase in glass transition temperatures with nanofiller loading levels is discussed, drawing attention to the aggregated filler effect and the disentangling of silicone chains with increasing interfacial interaction. TGA analysis revealed an early onset of degradation with increase in nano aluminum nitride loading levels. Thermal conductivity increased with nanofiller loading levels, peaking at 3 phr by weight. Dielectric studies of breakdown strength and frequency domain spectroscopy from 1 mHz to 1 KHz is studied under different thermal points. The results are presented and discussed here.