In situ exfoliation of graphite oxide nanosheets in polymer nanocomposites using miniemulsion polymerization

Poly(styrene-co-butyl acrylate) (poly(St-co-BA)) nanocomposite latices based on graphene oxide (GO) were synthesized by miniemulsion polymerization. The polymerization procedure involved dispersing an aqueous solution of graphite oxide in a monomer phase, followed by emulsification in the presence of a hydrophobe and a surfactant into miniemulsions. The focus was to investigate the suitability of miniemulsion for the synthesis of polymer nanocomposites based on a graphene derivative (i.e., GO) with exfoliated structure in a one-step nano-incorporation technique. Poly(St-co-BA) nanocomposites containing the exfoliated GO nanoplatelets, which have improved mechanical and thermal properties were successfully synthesized by the miniemulsion process. The nanostructure of the nanocomposites was investigated by transmission electron microscopy (TEM) and X-ray diffraction (XRD). TEM and XRD indicated that the nanocomposites mainly showed exfoliated morphologies, except at relatively high GO content. TEM also revealed that the nanocomposite latices had the so-called ‘‘armored’’ structure, where the nanosized GO sheets are distributed around the edges of the copolymer particles.