Ultrasound–assisted synthesis and characterization of polymethyl methacrylate/reduced graphene oxide nanocomposites

This paper reports ultrasound–assisted synthesis of polymethyl methacrylate (PMMA)/reduced graphene oxide (RGO) nanocomposites by in–situ emulsion polymerization coupled with in–situ reduction of graphene oxide. The thermal degradation kinetics of the nanocomposites was also assessed with Criado and Coats-Redfern methods. Intense micro-convection generated by ultrasound and cavitation results in uniform dispersion of RGO in the polymer matrix, which imparts markedly higher physical properties to resulting nanocomposites at low (≤ 1.0 wt%) RGO loadings, as compared to nanocomposites synthesized with mechanical stirring. Some important properties of the PMMA/RGO nanocomposites synthesized with sonication (with various RGO loadings) are: glass transition temperature (0.4 wt%) = 124.5°C, tensile strength (0.4 wt%) = 40.4 MPa, electrical conductivity (1.0 wt%) = 2 × 10−7 S/cm, electromagnetic interference shielding effectiveness (1.0 wt%) = 3.3 dB. Predominant thermal degradation mechanism of nanocomposites (1.0 wt% RGO) is 1-D diffusion with activation energy of 111.3 kJ/mol. This article is protected by copyright. All rights reserved.