Localization of Poly(glycidyl methacrylate) Grafted on Reduced Graphene Oxide in Poly(lactic acid)/Poly(trimethylene terephthalate) Blends for Composites with Enhanced Electrical and Thermal Conductivities

Interfacial localization of conductive fillers in a cocontinuous immiscible polymer blend is an efficient way of improving the electrical and thermal conductivities of the composite. Conductive path formation at the interface of a cocontinuous structure is expected to provide high conductivity by a smaller amount of the filler, which can be used for applications as conductive materials. In this study, biobased poly(lactic acid) (PLA) was blended with poly(trimethylene terephthalate) (PTT) to make the cocontinuous immiscible polymer blend. Poly(glycidyl methacrylate) (PGMA) was grafted on reduced graphene oxide (rGO) to make a PGMA-grafted rGO (rGO-PGMA). The epoxy group of GMA on rGO-PGMA reacted with the end groups of both PLA and PTT and localized at the interface between PLA and PTT by a two-step blending procedure to form the conductive path between PLA and PTT. From transmission electron microscopy observation, it was found that rGO-PGMA localized between the interface of PLA and PTT. Both electrical and thermal conductivities of the composite were improved, which was confirmed by the electrical volume resistivity and thermal diffusivity measurements, compared with neat polymers and other blends.