New preparation approach, electrical and mechanical properties of poly(vinyl alcohol)-loaded graphene films

Previous publications showed that graphene sheets polymer nanocomopsites were prepared by incorporating previously prepared graphene into the polymer matrix through two or more successive steps. In this work, graphene sheets were exfoliated from graphite inside the polymer matrix solution for certain period in one step. This approach was easy to perform, low cost, high mass production of graphene and, almost, produces effective results. In this respect, electrolytic solution from poly(vinyl alcohol) (PVA) and salt was prepared and exfoliation process took place inside it for different times. After that, solution was dried to get films of PVA loaded with different concentrations of graphene sheets. Scanning electron microscopic and transmission electron microscopic images of exfoliated graphene sheets were studied. Raman spectroscopy of graphite, graphene nanosheets, and PVA-loaded graphene was studied. The dielectric permittivity, dielectric loss, and alternating current electrical conductivity were studied and had maximum values at 10 min of exfoliation time. Cole-Cole impedance plots show semicircles behavior with lowest radius for samples prepared at 10 min. The elastic modulus was found to have a maximum value at exfoliation time of 30 min.