Salt template-assisted construction of three-dimensional interconnected network in thermally conductive EP/PVDF/NiCo@GNP composites

Abstract

In this study, graphene nanoplatelets (GNP) and nickel–cobalt (NiCo) alloy were adopted as reinforcing materials to prepare epoxy (EP) resin-based composites. NiCo particles were able to achieve uniform anchoring on GNPs’ surface under the electrostatic force due to the successful introduction of oxygen defects on GNPs. With the synergistic effect of adhesive PVDF and salt particles, the system with three-dimensionally (3D) interconnected network was successfully constructed. Benefit from the formation of mechanically stable and efficient heat conduction paths, the thermal conductivity (TC) of the EP/PVDF/NiCo@GNP composite reached 1.077 W⋅m−1⋅K−1 at a filler volume fraction of 6.82 vol%, while the counterpart’s storage modulus (E’) was up to 3.22 GPa. In addition, a scaling formula was quantitatively proposed to correlate TC with E’, and the perfect agreement between the theoretical prediction and experimental data clarified the underlying mechanism of the relationship between phonons transport and stress transfer within a system with 3D ordered structures. The establishment of relationship between AHR (average heating rate) and TC made it possible to further predict TC of composites based upon the infrared thermal imaging (ITI) data. The as-prepared GNP composites show good application prospects as thermal management materials which need to experience thermally mechanical deformation.