Increasing heat transfer performance of thermoplastic polyurethane by constructing thermal conduction channels of ultra-thin boron nitride nanosheets and carbon nanotubes

Abstract

Thermal interface materials (TIMs) have become more and more necessary in miniaturized modern devices, so the exploration of highly thermally conductive TIMs with flexibility and elasticity are of great significance. Herein, a polymer-based thermoplastic polyurethane (TPU) composite membrane with high thermal conductivity, flexibility and elasticity was conveniently prepared via constructing thermal conduction channels of ultra-thin hexagonal boron nitride nanosheets (h-BNNSs) and carbon nanotubes (CNTs). Then the maximum thermal conductivity of h-BNNSs/CNTs/TPU composite is up to 1.35 W m⁻¹ K⁻¹, increasing thermal conductivity of original polymer TPU by about 513%. The excellent thermal conductivity is attributed to the construction of the multi-channel heat transfer structure among the ultra-thin h-BNNSs with good in-plane thermal conductivity and CNTs. Moreover, the composite membrane has fantastic insulation and it can be stretched to at least 300% of its original length. Therefore, the fabricated h-BNNSs/CNTs/TPU composite membrane has great potential as important TIMs in thermally conductive applications.