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

• Published in: International journal of heat and mass transfer 2024-12, Vol.234, p.126125, Article 126125
• Main Authors: Ruan, Haoou, Fan, Sidi, Zhang, Yixiao, Liu, Yunpeng, Song, Jingxuan, Lv, Fangcheng, Yu, Xiang
• Format: Article
• Language: English
• Subjects: Aramid fiber; Electrical property; Filler-size matching; Thermal property
• ISSN: 0017-9310
• DOI: 10.1016/j.ijheatmasstransfer.2024.126125

•A filler matching strategy for BN/PMIA composites was implemented through amino-coupling agent surface treatment and the wet papermaking process.•The electrical insulation and thermal conductivity of the composite paper were enhanced by adjusting the filler matching ratio.•A finite element model was developed to elucidate the mechanisms underlying the improvements in both electrical and thermal properties. 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.