Enhanced thermal conductivity in polyamide 6 composites based on the compatibilization effect of polyether-grafted graphene

Abstract Industries have been longing for highly thermally conductive polymer materials to cool the heating cores in modern electronics. Graphene-reinforced thermoplastic polymer, though supporting the mature technologies in producing heat sinks and plastic shells applications, often fails to realize its full potential in thermal conductivity (TC) due to the limited graphene loading and poor filler dispersion. Aiming at improving graphene/polyamide 6(PA6) interface, a filler/polymer compatibilization approach through grafting polyamide-miscible polyether components on graphene sheets (GSs) is proposed in this work through sequential dopamine and silane treatment. The PA6 composites filled with controlled loading of treated and untreated GSs were fabricated through extruding process. Compared to unmodified GSs, drastically reduced melt viscosity and enhanced filler dispersion are realized in modified GSs filled PA6 composites allowing further loading of GSs up to 28 wt% that enables the unprecedented out-of-plane TC of 6.13 W m−1 K−1. Besides, effective medium theory simulations suggest the significantly reduced interfacial thermal resistance in treated GSs filled composites at above percolation threshold, indicating the formation of thermal conduction network in these samples owing to the homogeneously distributed fillers. These results address the significance of graphene compatibilization approach in producing processible, highly loaded and well dispersed GSs/PA6 composites towards the design and application of highly thermally conductive materials for thermal management in advanced electronics packaging.