A Novel Route for Well-Defined Polystyrene-Grafted Multiwalled Carbon Nanotubes Via the Radical Coupling Reaction

Multiwalled carbon nanotubes-graft-polystyrene (MWNTs-g-PS) was synthesized by atom transfer nitroxide radical coupling chemistry. MWNTs with 2,2,6,6-tetramethylpiperidine-1-oxy (MWNTs-TEMPO) groups was prepared first by esterification of 4-hydroxy (HO)-TEMPO and carboxylic acid group on the surface of MWNTs (MWNTs-COOH); PS with bromide end group (PS-Br) were then obtained by atom transfer radical polymerization using ethyl 2-bromoisobutyrate as initiator and CuBr/N,N,N',N '',N ''-pentamethyldiethylenetriamine as catalyst. The MWNTs-TEMPO was mixed with PS-Br and heated to 90 degrees C in the presence of CuBr/PMDETA to form MWNTs-g-PS. The product was characterized by FTIR, NMR, TGA, and TEM. TEM indicates that the MWNTs are enveloped by the polymer molecules. The content of grafted polymers is 46.7% by TGA measurements when the number-average molecular weight (M-n) of PS-Br is 10,200 g/mol. The as-prepared nanocomposites exhibit relatively good dispersibility in solvents such as CH2Cl2, THF, and toluene. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 114: 1914-1920, 2009