Evaluation of Dielectric Constants of PLA/PHA with 100-nm Aluminum Particles Using a Modified Paletto-Furukawa Expression

The incorporation of nanofillers into polymer matrices has been in the limelight for its versatile capabilities as polymer nanocomposites in electrical applications. In this investigation, the dielectric constants of polylactic acid/polyhydroxyalkanoates biopolymer composite with aluminum nanofillers were evaluated. Employing standard fabrication and testing procedures, the highest dielectric constant was observed at PLA-PHA-Al at 15 vol % loading of nanofillers, which was exactly 5.5, denoting a high-k biopolymer composite fabrication. The experiment results were compared with a modified Paletto expression with consideration of mathematical formulae that conform with continuous nanoparticle dispersion and the presence of interphase regions that alter dipole moments within the composite. The Furukawa model for predicting dielectric constant was employed to modify the Paletto expression in terms of atomic and interphase distances of the nanofiller employed. The comparison that was made vividly describes the discrepancy between experimental and theoretical evaluations, whereby factors, such as impurities, and the formation of dipole moments between interphase regions could have affected the charge-storing capacity of the fabricated biopolymer composite.