Effect of Graphene Nanoplatelets (GNP) on the Dielectric and Thermal Properties of Polystyrene (PS)/Polyvinylidenedifluoride (PVDF) Blends

Polymer films are of much importance in the development of capacitor technology because of their unique properties such as high breakdown strength, good stability and economic viability. The disadvantage of low dielectric constant for polymers can be overcome by incorporating various fillers into them. In this study, polystyrene (PS) blend with 50 volume percentage (vol%) polyvinylidenedifluoride (PVDF) is prepared and graphene nanoplatelets (GNP) in different weight percentages (0 to 15 wt%) are added to this blend to prepare PS/PVDF/GNP nanocomposites. The preparation of blend and its nanocomposites is carried out using melt mixing technique followed by hot pressing. Thermo gravimetric analysis and differential scanning calorimetry studies indicated that the nanocomposites exhibited better thermal stability than the blend. Dielectric properties of nanocomposites are measured at room temperature in the frequency range of 10 Hz to 1 MHz using a dielectric impedance analyzer. Dielectric constant of PS/PVDF blend is found to increase with increasing GNP loading. For PS/PVDF-50 vol% blend with 15 wt% GNP, dielectric constant as high as 71 and dielectric loss of 0.28 are obtained at 100 Hz. By incorporating GNP in PS/PVDF blend, the dielectric constant is enhanced and these nanocomposites can be a potential candidate material for dielectric or capacitor applications.