Endowing Thermally Conductive and Electrically Insulating Epoxy Composites with a Well-Structured Nanofiller Network via Dynamic Transesterification-Participated Interfacial Welding

It is urgently required to achieve good thermal conductivity and electrical insulation performance in polym-based composites with the minimum incorporation of functional fillers. In this work, the selective distribution of multiwalled carbon nanotubes (MWCNTs) in the segregated network of hexagonal boron nitride (h-BN) in the epoxy vitrimer matrix was achieved by compression molding, in which interfacial welding was enabled by small-molecule-participated dynamic transesterification at elevated temperatures. Due to the synergistic contribution of the well-structured nanofiller network, the epoxy vitrimer composites demonstrate enhanced thermal conductivity and electrical insulation at low filler content. The composite containing 1 wt % of MWCNTs and 8 wt % of h-BN shows thermal conductivity and electrical resistivity of 0.83 W/(m.K) and 1.92 x 10(11) Omega.cm, respectively. The electrical resistivity can be further improved by increasing the segregated h-BN content. This method provides a novel way to prepare cost-effective polymer composites with excellent thermal conductivity and electrical insulation.

Automated summary

In this study, the selective distribution of multiwalled carbon nanotubes and hexagonal boron nitride in an epoxy vitrimer matrix was achieved through compression molding, resulting in polymer composites with enhanced thermal conductivity and electrical insulation.