Filler-size matching strategy for highly thermal-conductive insulating BN/PMIA composite paper

Abstract

PMIA paper has received intensive interests because of its ultrahigh mechanical properties and insulating potential as an ideal packaging material for electrical and electronic devices. However, its low thermal conductivity arouses the risk of heat breakdown. In this study, the filler-size matching strategy is proposed by combining micro- and nano-scale BN fillers for the preparation of BN/PMIA composites. 15 wt% BN/PMIA composites have better thermal conductivity and breakdown strength than PMIA and each parameter could be pertinently improved by adjusting the matching ratio. The enhanced thermal conductivity of 205% is achieved at micro-BN dominated composites by constructing an effective heat flow pathway. The breakdown strength is increased by 48% in the composites governed by nano-BN, which acts as the scattering center for the electron transport that impedes the discharge process. Wet-laid PMIA composite papers can be tailored by matching filler sizes to achieve either high thermal conductivity or excellent insulation strength while maintaining stable mechanical performance. Assisted with the theoretical studies, our results provide a deeper understanding of the filler-size matching strategy in the polymer matrix.