Microwave-Induced Chemical Functionalization of Carboxylated Multi-Walled Nanotubes With 2,3-diaminopyridine

Abstract

In this paper, the microwave-induced chemical functionalization of carboxylated multi-walled carbon nanotubes (MWNT-COOH) by 2,3-diaminopyridine, have been investigated. The major advantage of this high-energy procedure is reducing the reaction time to the order of minutes and the number of steps in the reaction procedure compared to that of conventional functionalization processes. These functionalizations involve amidation and cycloaddition reactions, respectively. The amidation was completed in one step as compared to two in the conventional approach. The acid chloride formation step was eliminated here. The cycloaddition of MWNTs with triphenylphosphite to producing MWNT-4-azabenzimidazole was carried out in 20 minutes under microwave conditions, and the results were similar to what was achieved in 4 days using conventional methods. The interesting point is that modified MWNT can be homogeneously dispersed in DMF without sonication and the dispersed MWNT does not sediment in 1 month. The results are confirmed by FT-IR, SEM, RAMAN, TGA, DTA and elemental analysis.