(711b) Polymer Nanocomposites; Highly Conductive Graphene/Polycarbonate Nanocomposites

Highly dispersed graphene (C-FGS) polycarbonate nanocomposites, 0.05-4 wt%, with excellent electrical and mechanical properties were prepared using both emulsion mixing and solvent blending methods. The lowest percolation volume fraction was obtained from emulsion mixing method. The storage tensile modulus of the nanocomposites prepared by solution blending method was higher than the neat polycarbonate. The storage tensile modulus of these composites increased with increasing graphene content. The modulus decreased when the graphene weight percent increased to 4wt%. The impact of the addition of the graphene on the modulus to the composite prepared by emulsion method was lower than the composites prepared by solution blending. The glass transition temperature of the emulsion composites were decreased by the increasing graphene content. The glass transition temperature of the solution blended composites showed only slight decrease. The area under the peak decreased for both composites series. The AC impedance spectroscopy examination of the composites showed a frequency independent behavior followed by frequency dependent behavior for the percolated composites. The real component of conductivity was decreased when the temperature increased. The conductivity of the composites with graphene above percolation volume fraction exhibited an ohmic frequency independent behavior. The morphology of the composites were examined by SEM, TEM, and small angle neutron scattering. Stack disk model was used to provide quantifying information about the number of graphene layers per stack and average disk dimensions.