Water-borne graphene-derived conductive SBR prepared by latex heterocoagulation

Abstract

Water-borne conducting SBR (styrene butadiene rubber) composites containing surface-modified multi-layered graphene sheets (MLGSs) were prepared using a simple heterocoagulation process. Three different types of MLGSs were used and compared; raw, carboxylated, and cetyltrimethyl ammonium bromide (CTAB)-stabilized MLGSs. The SBR latex was mixed with a well-dispersed MLGS aqueous dispersion and heterocoagulated using a flocculant, polyaluminium chloride (PAC), at elevated temperatures. After particle growth and successive stabilization steps, the particulate SBR/MLGS composites were prepared in the size range, 10–100 μm. The CTAB-stabilized MLGSs were dispersed more effectively in the SBR matrix owing to their electrostatic attraction with the negatively charged SBR colloid particles. The MLGS-containing the SBR composites showed improved thermal stability and electrical conductivity. Importantly, the percolation threshold for the electrical conductivity was achieved at a low MLGS concentration, i.e., 0.5 wt%, using this heterocoagulation process.