Enhanced mechanical property, thermal and electrical conductivity of natural rubber/graphene nanosheets nanocomposites

Graphene nanosheets (GNs) were prepared by supercritical solvent intercalation method and cyclic stripping method under high pressure and stress. This non-chemical method reduces impurities and avoids the destruction of graphene's intrinsic structure. In order to decrease the secondary stacking in processing, firstly GNs were dispersed in natural rubber (NR) latex to prepare NR/GNs concentrated master batch, and then combined with solid NR by mechanical blending. Since GNs have good dispersion in rubber matrix, a strong intermolecular force is formed between GNs and NR. Tensile strength, elongation at break, stress at 100% strain, stress at 300% strain, and tear strength of NR/GNs nanocomposites with 2 wt% GNs are enhanced 59.53%, 17.85%, 67.07%, 80.12% and19.20% respectively compared with NR. With more GNs, the NR/GNs nanocomposites exhibit lower T-g and better thermal stability. When the content of GNs in NR/GNs nanocomposites reaches 2 wt%, the T-g of nanocomposites drops about 2 degrees C, and the remaining carbon at 600 degrees C of nanocomposites increase by 3.07%. Moreover, It is demonstrated that the NR filled with 2 wt% GNs possess excellent thermal conductivity of 0.24 W m(-1) K-1?which is a 50% increment compared with pure NR. Meanwhile, the electrical conductivity of the composites increases by four orders of magnitude than that of pure NR. These results clearly indicate that GNs can be expected to be manufactured at large scale and utilized in heat-conducting and antistatic rubber.