Poly(methyl methacrylate)-vapor growth carbon fiber-graphene nanocomposites prepared using supercritical CO2 mixing and drying

Supercritical carbon dioxide (scCO(2)) has been employed in conjunction with vapor growth carbon fibers (VGCFs) and graphene nanoplatelets (GNPs) to enhance the properties (electrical, thermal, physical) of a poly (methyl methacrylate) (PMMA) matrix. When the VGCF loading was 10 wt.%, the electrical conductivity (9.33 S/m) of the PMMA-VGCF nanocomposite prepared through scCO(2) mixing at 103.4 bar and 40 degrees C was 15.6% greater than that obtained when using traditional mixing in N-methyl-2-pyrollidone (NMP). A synergetic effect existed for the VGCFs and GNPs, with the thermal conductivity of the PMMA-VGCF-GNP nanocomposite [0.492 W/(m K)] being 20.2% greater than that of the individual PMMA-VGCF nanocomposite [0.409 W/(m K)], after applying scCO(2) mixing. The advantages of the proposed scCO(2) technology are twofold: it enhances the dispersion of VGCFs and GNPs in the PMMA matrix and eliminates residual NMP after scCO(2) drying.