Dielectric and Mechanical Properties of Silicone Rubber Composites Reinforced by Conductive Carbon Black and Neopentyl Glycol Diglycidyl Ether

Abstract

In the present investigation, dielectric, tensile strength, fracture toughness, and stress-strain properties of silicone rubber (SR) dispersed with carbon black (CB), and neopentyl glycol diglycidyl ether (NPGDE) (5 wt%, 10 wt%, and 12 wt%) were studied. Flake-like agglomerated morphology was confirmed from SEM (scanning electron microscope) studies as the CB@NPDGE filler concentration increases in the SR matrix. Surface area (354-358/cm(3)/g/A), pore size, and pore diameter (2.89 nm) remarkably increased for SR: CB@NPDGE polymer composites when compared with virgin SR. TGA spectra showed an increase in the decomposition temperature (600 degrees C) for SR: CB/NPDGE polymer composite when compared with virgin SR. A slight shift in the wavenumber of the functional groups resulted as the CB@NPDGE concentration increases in the SR polymer matrix. Optical absorbance shift towards the right side of the spectrum (redshift), broadened as CB@NPDGE concentration increased in SR polymer and optical band gap (E-g) decreases from 3.50 eV to 2.64 eV. SR:CB@NPDGE (10 wt% and 12 wt%) displayed improved dielectric properties having dielectric constant (1.68 x 10(3) , 4.87 x 10(3)), dielectric permittivity (10(1)-10(3)/ 10(4)), and dielectric loss (<1.1/0.05) when compared with virgin SR. Significant improvements in the stress-strain and tensile strength properties resulted for SR:CB@NPDGE (10 wt% and 12 wt%) polymer composites. Compressive strength and tensile strength were found to be similar to 12.909 MPa and similar to 136.2 MPa. The peak load is between 0.254 kN to 1.9071(N. The elongation at break for SR:CB@NPDGE (12 wt%) polymer composite was found to be 97.14% with 14.07 kN/mm of stiffness. An increase in temperature leads to an increase in dielectric permittivity and ac conductivity for different wt% of CB@NPDGE in SR polymer composites. Further, tensile strength, and tensile strain to failure decreases monotonically with an increase in temperature (100 degrees C). The present research gives a pathway for the development of organic hybrid polymer-reinforced composite structures for piezoelectric, dielectric, and structural applications.