Abstract
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•Modified graphene imparts thermal stability to Poly (styrene-co-methyl methacrylate) [P(st-mma)].•The thermal stability of P(st-mma) decreased with microwave irradiation.•The thermal stability of P(st-mma)/MG nanocomposites increased with irradiation time up to 10min and decreased subsequently.•The degradation of P(st-mma) and P(st-mma)/MG is governed by random scission model.
Poly (styrene-co-methyl methacrylate) [P(st-mma)] composite containing 0.1wt% modified graphene (MG) was prepared via melt blending. MG was prepared by oxidation method using nitric acid. The P(st-mma) and P(st-mma)MG composite were irradiated using microwave radiation. The degradation mechanism and thermal stability of the irradiated and un-irradiated samples was analyzed by TGA. P(st-mma)MG showed high thermal stability. The average activation energy of thermal degradation was found to be 200kJ/mol for P(st-mma), 214kJ/mol for P(st-mma)MG. The activation energy was highest for 10min irradiated nanocomposites indicating an improvement in stability. The degradation mechanism was investigated by comparing the master plots constructed using the experimental data with theoretical master plots of various kinetic models. The thermal degradation of P(st-mma) and P(st-mma)MG composite before and after irradiation governs the random scission mechanism. SEM and TEM micrographs showed improved interactions and degradation of composites after 10min and 20min irradiation respectively.