Improving thermal conductivity of phthalonitrile composite through constructing three-dimensional graphene networks and interfacial engineering

Achieving high thermal conductivity for polymer composite with low filler loading is still a challenge. Here, phthalonitrile (APN)/few-layer graphene (FLG) composite with high thermal conductivity was successfully prepared by constructing three dimensional (3D) thermally conductive pathways. Such 3D structure was formed by hot compressing APN@FLG core-shell structures. The results showed that the thermal conductivity of APN@FLG composites with only 30 wt% of FLG was up to 11.4Wm⁻¹K⁻¹, which was 57 times to that of the pristine resin (0.2 Wm⁻¹K⁻¹). Such high thermal conductivity was attributed to the 3D connected thermally conductive networks. Furthermore, benefited from the high thermal stability of APN matrix, the as-prepared composite also showed high T₅ (temperature of mass losing 5 %) of higher than 500 °C. The composite with both high thermal conductivity and heat resistance are expected to be an idea candidate for high temperature thermal management applications.