Super-high thermal conductivity of polyamide-6/graphene-graphene oxide composites through in situ polymerization

Graphene is often used to improve the thermal conductivity of polymers but usually with high amount. The key factor that limits the thermal conductivity is graphene agglomeration as well as the incompatible interface between graphene and polymer. Here, we report super-high thermal conductivity of polyamide-6 (PA6) composites achieved by adding small amounts of graphene oxide (GO)-stabilized graphene dispersions (graphene-GO). The introduction of GO not only acts as an effective dispersant for graphene due to the non-covalent -stacking interactions but also participates in PA6 polymerization. Therefore, the issues associated with graphene dispersion in PA6 can be resolved and the interface adhesion enhanced by adding small amounts of graphene-GO. Furthermore, this approach reduces the tendency for decreased crystallinity. All these factors enhance the formation of heat conducting pathways among the graphene sheets. Thus, compared with graphene, graphene-GO enhances thermal conductivity at lower filler loading levels by enhancing graphene dispersion and interface adhesion.