Effects of crosslink density on the behavior of VHB 4910 dielectric elastomer

Abstract

Interpenetration of dielectric elastomers with fillers is an effective technique to improve requisite properties for voltage induced electromechanical performance. However, the requirement that the rigid frame has to maintain its pre-strained state, and time/temperature related phenomenon like stress relaxation/concentration, strain-induced crystallization and void propagation etc., limits this technology. To overcome these limitations, thermochemical and UV irradiation techniques of polymerization are used to modify the macromolecular structures of VHB 4910 elastomer with crosslink monomers. Both the methods are compared in terms of the modification in surface and molecular structure through optical microscope and infrared spectroscopy, respectively. Thermochemically modified samples are found flawless with regular surface reformation; crosslink density is evaluated and its influences on hysteresis, dielectric constant and material degradation at elevated temperature are characterized. Results from this study may contribute towards the complete understanding of space density for inclusion of filler, used for material development with user-defined properties.

Keywords:

• Interpenetration
• electromechanical
• macromolecular
• thermochemical
• UV irradiation
• molecular

Acknowledgment

The authors acknowledge the help rendered by the Department of Science and Technology, Govt. of India, New Delhi, for funding this research through grant file no. ECR/2016/000585 dated 27-09-2016.