Effect of Graphene Encapsulated Styrene-butyl Acrylate Copolymer Microspheres on Enhancing the Dielectric Properties of Polymethyl Methacrylate
Abstract In this work, the dielectric properties of polymethyl methacrylate (PMMA) were obviously improved by using graphene encapsulated microspheres through soap-free emulsion polymerization technique. Scanning electron microscope (SEM) observation implied that styrene-butyl acrylate copolymer (SBA) microspheres and reduced graphene oxide encapsulated SBA microspheres (rGO@SBA) was successfully obtained through using soap-free emulsion polymerization. The dielectric constant of PMMA/rGO@SBA could reach 46.64 at 1000 Hz by incorporating only 0.26 wt% rGO. On the other hand, three different PMMA based composites were also prepared by adding rGO and SBA through conventional emulsion polymerization and simple physical blending. The dielectric constant results revealed that all these composites presented low dielectric constant compared with composites through soap-free emulsion polymerization technique. The possible reason was that the isolated rGO sheets can interconnect with each other to from three-dimensional segregated network structure through hot pressing technique. SEM results demonstrated that the rGO encapsulated SBA structure could be retained after hot pressing. Therefore, soap-free emulsion polymerization technique can favorably fabricated rGO encapsulated polymer microspheres with high dielectric properties.
