Highly Thermally Conductive Composites Fabricated by Electrospinning of Ketoamined PEEK with fBNNSs@fMWCNT and Hot-Pressing

Thermally conductive and electrically insulating polymer composites exhibit significant advantages in thermal management applications, which are attributed to their broad applicability, facile processing characteristics, and favorable cost-performance ratio. In this study, composites with the above performance are achieved by incorporating hydroxylated boron nitride nanosheets (fBNNSs) into the poly(ether ether ketone) (PEEK) matrix. Additionally, carboxylated multiwalled carbon nanotubes (fMWCNTs) were introduced to bridge the dispersed fBNNSs, thereby significantly enhancing the thermal conductivity of the composite while preserving its electrical insulating properties. To construct a continuous thermally conductive network, the electrospinning technique is utilized to align the fillers within the matrix. In order to overcome the difficulty caused by PEEK insolubility for use in the electrospinning process, soluble poly(aryl ether ketone imine) (PEEKt) was synthesized to facilitate the formation of a nanofiber membrane, which undergoes an acidolysis treatment and successfully regenerates the PEEK main chain structure while preserving the fiber morphology intact. After hot-pressing molding, the thermal conductivity (λ) of the composite reaches 6.02 W/(m·K), and the electrical insulating performance remains 1016 Ω·cm orders of magnitude when the weight ratio of fBNNSs to fMWCNT is 25:1. This study provides an innovative methodology for the preparation of a PEEK-based composite with high thermal conductivity and electrical insulation properties utilizing electrospinning followed by hot-pressing.