Calculation method for the dielectric constant of thioglycolic acid grafted modified SBS dielectric elastomer

Abstract

Nonpolar/polar block copolymer materials can be used to develop high-performance dielectric elastomer materials. At present, there is no method to accurately predict its dielectric constant, which is not conducive to improving related research and development efficiency. For this, styrene–butadienestyrene triblock copolymer (SBS) block copolymer grafted modified by thioglycolic acid (TGA) is chosen as the research object. We propose a hybrid calculation method combining the group contribution method, the connectivity index method, and the dipole moment fluctuation method. The connectivity index method and the dipole moment fluctuation method calculate the dielectric constants of nonpolar and polar repeat units to provide accurate basic data for the group contribution method. In the calculation process, the Vogel model completes the mutual conversion between dielectric constant and molar polarizability. Both theoretical calculation and experimental verification show that the dielectric constant of SBS-TGA increases with the grafting rate. We found the correlation between theoretical calculations and experimental values and confirmed that the applicable frequency range of this method is 1 kHz–1000 kHz. This method can be extended to predict the dielectric constant of other polymers and improve development efficiency.

Keywords

• Dielectric constant
• Modified SBS
• Group contribution
• Connectivity index
• Dipole moment fluctuation