Microwave-induced rapid nanocomposite synthesis using dispersed single-wall carbon nanotubes as the nuclei
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Single-wall carbon nanotubes (SWNTs) provide a reactive environment in presence of microwave radiation because they absorb the energy that leads to fast, direct heating. This makes composite formation in a microwave reactor highly feasible where the SWNTs serve as the nuclei for polymerization. In this article, we demonstrate rapid, in situ synthesis of poly(methyl methacrylate) (PMMA) and polyvinylpyrrolidone (PVP) nanocomposites using their respective monomers. The key to their success was the use of the highly dispersible SWNTs, which had strong interactions with the monomer and the polymer. Rapid synthesis within a few minutes was possible, which led to remarkable nano-scale dispersion of nanotubes in polymer matrix by encapsulation of the already dispersed SWNTs before the latter could agglomerate. The molecular weight and polydispersity of the polymers remained unchanged in the presence of the SWNTs. The addition of 0.5 wt% SWNT to PMMA enhanced its thermal stability (as measured by the initial degradation temperature) by 37 °C and the hardness by around 50%. On the other hand, with the addition of up to 4 wt% SWNT, the PVP showed no enhancement in thermal stability but its hardness increased by 250–300%. Finally, this technique is practical because it reduces time, cost, and energy requirements.
KeywordsPMMA Microwave Radiation AIBN Composite Formation Microwave Reactor