A simple method is reported to coat silicon carbide (SiC) nanoparticles with polystyrene (PS) to improve the interfacial adhesion between polymer matrix and SiC nanoparticles. The morphology of untreated SiC nanoparticles, PS coated SiC (p-SiC) nanoparticles, SiC/PS nanocomposites, and p-SiC/PS nanocomposites are observed. The HRTEM image of p-SiC shows that the thickness of PS on the surface of SiC is about 1.5-2.0 nm, which is consistent with the TGA results. With 24.7 vol % untreated SiC nanoparticles dispersed into PS matrix, the thermal conductivity () of the SiC/PS composites increases by about 192%. However, when the same volume fraction of p-SiC nanoparticles is used, the increase is about 353%. This big difference could be attributed to the promoted dispersion of the p-SiC in the PS matrix. The measurements of glass transition (T-g), dielectric constant (epsilon), and tensile strength at break (sigma(b)) also support this explanation. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013