Reduced graphene oxide / epoxy nanocomposites with enhanced dielectric, mechanical, thermomechanical and thermal properties

Abstract

Epoxy/conducting filler nanocomposites with high dielectric performance have emanated as a promising material in electronic and electrical industry. In this work, a facile and low-cost method, that is, thermal reduction at 400°C was adopted for the preparation of reduced graphene oxide (rGO) from graphene oxide (GO). The rGO was characterized by X-ray diffraction analysis, Fourier transform infrared spectroscopy, Raman spectroscopy, Field emission scanning electron microscopy and Transmission electron microscopy. Epoxy nanocomposite presented a dielectric permittivity of 35 at 1.8 vol.% loading of rGO (Ep/G-1.8) at 103 Hz, which was 5 times higher than neat epoxy and with a low dielectric loss. With the addition of 0.3 vol.% of rGO (Ep/G-0.3), the mechanical properties such as tensile strength, Young’s modulus and impact strength were enhanced by 34%, 56% and 54%, respectively. Dynamic mechanical analysis (DMA) revealed that in comparison to epoxy, there was a tremendous enhancement of storage modulus (55%) and the glass transition temperature (Tg) exhibited a remarkable shift of 39°C towards higher temperature for Ep/G-0.3. Cross-link density and coefficient of effectiveness (C-factor) estimated from the storage modulus improved significantlyfor Ep/G-0.3. Theoretical modelling was done on the viscoelastic properties of the composites. SEM studies indicated the uniform dispersion of rGO throughout in the epoxy matrix. Thermogravimetric analysis revealed that inclusion of rGO improved the thermal stability of epoxy nanocomposites.