Preparation of Poly(acrylic acid) Grafted Multiwalled Carbon Nanotubes by a Two-Step Irradiation Technique

Abstract

A facile strategy to prepare water-soluble multiwalled carbon nanotubes (MWNTs) by two steps of γ radiation is developed. First, MWNTs are irradiated in ethanol. The radiolysis of ethanol produces many active species such as •CH2CH2OH and •CH(CH3)OH which react with CC bonds on the surface of MWNTs. Afterward, poly(acrylic acid) (PAA) is covalently grafted to the surface of modified MWNTs by radiation in the presence of acrylic acid. FT-IR, 1H NMR, and TGA results showed that PAA chains were successfully grafted onto the surface of MWNTs. The TEM images also provide direct evidence of the formation of a core−shell structure, and the external diameter of resultant MWNTs is increased remarkably. The PAA-g-MWNTs have very good solubility in water and other polar solvents. This two-step grafting approach may also be employed introducing other functional polymer chains onto MWNTs.