Facile covalent functionalization of carbon nanotubes via Diels-Alder reaction in deep eutectic solvents

摘要

Deep eutectic solvents (DESs), a new type of cost-effective ionic liquid analogues, were employed to develop a novel and efficient method for direct functionalization of multiwalled carbon nanotubes (MWNTs) via Diels-Alder (DA) click reaction. Poly(ionic liquid) s featuring furfuryl moieties (P(F-ILs)) and butyl moieties (P(B-ILs)) were synthesized by the functionalization of poly(chloromethylstyrene-al t-maleic anhydride) with 1-methylimidazole and furfuryl amine or butylamine. Then, the polymer was directly grafted on the surface of untreated MWNTs in choline: ethylene glycol (ChCl:EG) based DES without any catalyst. The successful functionalization of the polymer on MWNTs was confirmed by Raman spectroscopy, TGA, and XPS analysis. It was shown that the reaction proceeded in a very rapid fashion (less than an hour) and the use of DESs significantly improved the grafting density (more than double) as compared with the reaction in water. (C) 2018 Elsevier B.V. All rights reserved.