The physicomechanical properties, curing characteristics, and morphological behaviors of styrene-butadiene rubber/graphite powder composites were evaluated. Different weight fractions and particle sizes of graphite powder were used. An increase in the graphite content increased the maximum torque, reinforcing factor, and tensile strength and decreased the elongation at break and equilibrium swelling. Also, a decrease in the particle size of the graphite increased the tensile strength and decreased the equilibrium swelling. Moreover, the dielectric properties were measured at about 30 degrees C and 100 Hz. The values of permittivity and dielectric loss were found to increase with increasing graphite content. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 298-304, 2011