A highly thermal conductive and compliant heterogeneous composite with strong interfacial strength controlled by the degree of vulcanization

Abstract

Thermal interface materials with high thermal conductivity (TC) and mechanical compliance were essential for electronic devices. In this work, a highly thermal conductive and compliant composite with strong interfacial strength was fabricated by multilayer-stacking partially vulcanized silicone rubber (SR)/graphite (Gr) composites (Heter-SR/Gr) with high and low Gr contents, and then fully cured by further hot pressing. The multi-step vulcanization endowed great orientation of Gr and covalent bond between layers, thus heightened TC, maintained the mechanical compliance and enhanced the interfacial strength, respectively. The out-plane TC reached 25.45 W/(m·K) with an overall Gr content of 60.94 wt%, the TC value of the homogeneous structured composite was only 11.15 W/(m·K); these were consistent to the FEA simulation results. Moreover, the stress of Heter-SR/Gr reached 2.24 MPa at 25% compressive strain, which was 35.82% lower than that of homogeneous composite (3.49 MPa). This facile strategy is expected to be promoted in the further applications.