Rheological and electrical properties of polystyrene nanocomposites via incorporation of polymer-wrapped carbon nanotubes

Carbon nanotubes (CNTs) are used as nanofillers in polymer nanocomposites to improve the properties of a matrix polymer because of their excellent properties. However, CNTs tend to aggregate due to the strong van der Waals force between CNTs. To solve the problem, surface-modified CNTs with hydrophilic polymers, such as polyvinyl pyrrolidone (PVP) and polystyrene sulfonate (PSS), were employed. Polystyrene (PS)/CNT nanocomposites were fabricated by latex technology, which is a suitable method for dispersing nanofillers in aqueous particle suspension. The effect of the incorporation of the modified CNT was significant, thereby resulting in increased modulus at lower frequencies when compared to that of neat PS. Electrical percolation thresholds of PS/PSS-wrapped CNT and PS/PVP-wrapped CNT nanocomposites corresponded to 0.39 and 0.52 wt.%, respectively. The PS/PSS-CNT nanocomposites exhibited higher rheological and electrical properties than the PS/PVP-CNT counterparts due to the hydrophilic nature of PSS with strong negative charge groups.