Dielectric and piezoelectric behaviors of cellulose/PVDF composite film preparation by melt mixing method

Abstract

Poly (vinylidene fluoride) (PVDF) and its copolymers are piezoelectric polymers with growing applications in sensors and actuators. Generally, PVDF demonstrates an ability to convert the mechanical energy into electrical energy and vice versa. In this research, poly (vinylidene fluoride-co-Hexafluoropropylene) (PVDF-HFP)/cellulose composites were fabricated via twin screw extruder to achieve the high dielectric and piezoelectric properties and also utilized as a touch sensor. Two sources of cellulose-based materials, extracted microcrystalline cellulose (MCC) from sugarcane bagasses in 1-20 wt.%, and extracted bacterial cellulose (BC) from Nata de coco in 1-5 wt.%, were provided as an appropriate filler to improve the dipole alignment of PVDF-HFP matrix. The cast film extruder was used to produce the transparent composite films with unique properties. The increment in β-phase crystalline presented with higher amount of cellulose, both MCC and BC. The dielectric constant corresponded to piezoelectric coefficient was enhanced from 2.00 of neat PVDF-HFP to 3.75 with 10 wt.% MCC loading and 3.25 with 5 wt.% BC loading. Besides, the presence of MCC and BC in the composite films leaded to an improvement in thermal properties, and mechanical properties in terms of Young’s modulus and tensile strength with no dimensional changes at 110 ℃ due to the excellent thermal, and mechanical properties of cellulose structure.