Electrically conductive poly(methyl methacrylate)-reduced graphene oxide/poly(styrene-co-acrylonitrile) composite with double percolative architecture

Abstract

A poly(methyl methacrylate) (PMMA)-reduced graphene oxide (rGO)/poly(styrene-co-acrylonitrile) (SAN) composite was fabricated, and its electrical conductivity was improved with a double percolation system. Powdery PMMA nanoparticles were coated on rGO sheets using miniemulsion polymerization. The rGO sheets were uniformly distributed in the PMMA nanoparticles, which prevented the aggregation of rGO sheets. Therefore, PMMA-rGO is rendered capable of dispersing in ethanol and then mixed with SAN powder. The PMMA-rGO/SAN composite was hot-pressed to segregate the rGO sheets in the PMMA phase. The co-continuous architecture of the rGO in the PMMA phase forms an effective conductive network that allows high electrical conductivity. The ratio of PMMA to SAN was set as 5:5 to optimize the continuous structure in the composite. The fabricated PMMA-rGO/SAN (5:5) composite exhibited a high electrical conductivity of 2.38–5 S cm−1, which is significantly higher than that of a neat polymer. Moreover, it showed an appropriate electrical percolation threshold for low rGO content. These results provide a simple and an effective approach to fabricate selective localized rGO sheets for a continuous conductive network. © 2020 Elsevier B.V.