Preparation of NBR/expanded graphite nanocomposites by simple mixing

Nanocomposites of acrylonitrile-butadiene rubber (NBR) and expanded graphite (EG) were synthesised by melt mixing. Before being mixed with the NBR, the expanded graphite was first sonicated for 10 h, and the powders obtained were then grounding in a ball mill for another 10 h. Scanning electron microscopy (SEM) of the sonicated graphite layers revealed that the expanded graphite was completely torn into nanoscale sheets. Transmission electron microscopy (TEM) of the NBR/EG composites indicated nanoscale dispersion of the EG within the NBR matrix. The mechanical properties of the NBR/EG nanocomposites showed a remarkable improvement in tensile strength. Dynamic mechanical analysis (DMA) showed that the EG imparted a higher storage modulus and lower glass transition temperature to the NBR matrix. The expanded graphite was effective in increasing the electrical conductivity of the composites.