Electrical, optical, and rheological properties of ozone-treated multiwalled carbon nanotubes-polystyrene nanocomposites

The functionalization of multiwalled carbon nanotubes was performed through the treatment of multiwalled carbon nanotubes with ozone using UV-ozone irradiation to improve their dispersion in polystyrene matrix. Multiwalled carbon nanotubes-polystyrene nanocomposites were prepared at different multiwalled carbon nanotubes weight ratios to investigate the effect of multiwalled carbon nanotubes loadings on the electrical, optical, and rheological properties of polystyrene matrix. The obtained results revealed that incorporation of functionalized multiwalled carbon nanotubes into polystyrene improved the electrical, optical, and rheological properties of neat polystyrene which indicated that multiwalled carbon nanotubes were well dispersed in the polymer matrix. Results obtained from DC and AC electrical measurements revealed that the percolation threshold was around 0.8 wt% multiwalled carbon nanotubes and incorporation of 3% multiwalled carbon nanotubes into polystyrene increased polystyrene electrical conductivity up to six orders of magnitude. Besides, increasing of multiwalled carbon nanotubes loadings increased the relative dielectric permittivity, dielectric loss, and loss tangent while decreased the total impedance of polystyrene matrix. Rheological results indicated that incorporation of multiwalled carbon nanotubes into polystyrene elevated the magnitudes of storage modulus and loss modulus up to two orders of magnitude with increasing of multiwalled carbon nanotubes loadings up to 3 wt%. Finally, the addition of multiwalled carbon nanotubes to polystyrene matrix enhanced the UV/visible absorption of polystyrene and decreased the optical energy gap with a total reduction ratio of 5.8% compared to neat polystyrene with increasing multiwalled carbon nanotubes loadings up to 2 wt%.