Industrial & Engineering Chemistry Research, Vol.59, No.8, 3413-3424, 2020
Polyvinylidene Fluoride/Hydrogenated Nitrile Rubber-Based Flexible Electroactive Polymer Blend and Its Nanocomposites with Improved Actuated Strain: Characterization and Analysis of Electrostrictive Behavior
A polyvinylidene fluoride (PVDF)/hydrogenated nitrile rubber (HNBR)-based flexible electroactive polymer blend was developed by generating a suitable morphology that showed a judicious combination of strength and flexibility. The blend, containing 30:70 wt/wt ratio of PVDF/HNBR, was thermoplastic elastomeric in nature and exhibited visible planar actuation in the presence of an electric field. To the best of our knowledge, the electromechanical actuation of the thermoplastic elastomeric blend has been reported for the first time. The maximum planar strain was 5%, and the actuation was triggered by the strong induced polarization in both PVDF and HNBR phases that gave rise to a high dielectric constant and low dielectric losses. The interphase between PVDF and HNBR was also very strong, which made the thermoplastic elastomer (TPE) susceptible to withstand high electric field. The TPE also exhibited a bending actuation of 0.6 mm at a low electric field of 20 kV/mm, promising enough to be used in microdevices. Addition of barium titanate (BT) nanoparticles increased the dielectric constant as they were homogeneously distributed in both the phases. The maximum planar actuation (similar to 10%) was observed at 10 wt % BT loading, whereas 5 wt % loading exhibited the maximum dielectric strength (similar to 120 kV/mm). At 5 wt % loading, the bending actuation was 0.9 mm at 20 kV/mm, which was 50% higher than that of unfilled TPE. Both the TPE and its nanocomposite also showed good history dependency in a cyclic electric field. In summary, the study provides an attractive and unexplored alternative of developing electromechanically active TPEs and their nanocomposites.