Synthesis and Dielectric Characterization of Nanographite Filled Polyglycerol Adipate (PGA) Nanocomposite

Nanographite powder (0.5 wt%) filled polyglycerol adipate (NGPGA) nanocomposite was prepared using adipic acid and glycerol as the starting material without any solvent. Polycondensation between equal molar ratio of glycerol and adipic acid using dibutyltin dilaurate as catalyst resulted in a high molecular weight branched aliphatic polyester which is biodegradable. FTIR spectra confirmed the esterification of glycerol by the acid. Completely dried samples were used for frequency and temperature dependent dielectric measurements. It was observed that at ambient temperature both the samples did not show any frequency dispersion. However, nanographite filled nanocomposite showed a higher dielectric constant than unfilled PGA polymer. This was attributed to the increase in the number of microcapacitors due to addition of nanographite fillers. Temperature dependent dielectric behaviour showed no appreciable change in the magnitude of dielectric constant till 50-60oC. These enhanced dielectric properties of nanocomposites, if combined with a high dielectric strength, render them as a potential material for energy storage devices like dielectric capacitors.