Silicone/expanded graphite (EG) composites were prepared by melt mixing and solution intercalation. The effect of EG content and preparation methods of composites on thermal conductivity of composites were investigated, and it was found that with increasing EG, the thermal conductivity increased, and solution intercalation method showed better effect than melt mixing method in improving the thermal conductivity of composites. Dynamic mechanical analysis (DMA) was used to reveal that the storage modulus (E') of SI-prepared composite is relatively greater than those of MM-prepared composite counterparts. The scanning electron microscopes (SEM) observation confirmed that striking increase of thermal conductivity might be attributable to higher surface-to-volume ratio of EG fillers. (c) 2007 Elsevier B.V. All rights reserved.