Mechanical and electrical studies of PVA/PVP blend filled with MWCNTs

Nanocomposite of polyvinyl alcohol (PVA)/polyvinylpyrrolidone filled with different mass fraction of multi-walled carbon nanotubes was prepared via traditional casting route. Mechanical properties including hardness, ultimate strength, toughness, Young modulus, and elongation at break show an obvious enhancement with increasing MWCNTs content up to a certain concentration (similar to 1%). Aggregations of MWCNTs in the higher filling levels may cause reduction in mechanical properties. The DC electrical conductivity was observed to be increased with increasing temperature and MWCNTs concentration. DC electrical conductivity measurements also show an abrupt increase in conductivity with the increase in MWCNTs concentration from 0.5 to 1.0% by weight, suggesting occurring of the percolation phenomenon. Dielectric measurements for the present samples were examined in a wide range of frequencies from 10(-1) to 10(7) Hz at various fixed temperatures (from 303 to 343 K). A decrease in dielectric loss and dielectric constant measurements was observed with increasing frequency and temperature. At 3% MWCNTs content, the dielectric loss and dielectric constant values obtained are maximum, reaching 2.4 x 10(7) for dielectric loss and 3.5 x 10(7) for dielectric constant. While dielectric loss and dielectric constant increase with increasing MWCNTs content, it was observed that the higher MWCNT present low dielectric loss and dielectric constant values due to MWCNTs aggregations.