Poly(ethylene oxide)-multiwall carbon nanotube composites: Effect of dicarboxylic acid salt-based modifiers

摘要

An investigation was carried out to improve the dispersion of multiwall carbon nanotubes (MWCNTs) in the poly(ethylene oxide) (PEO) matrix using a half-neutralized sodium salt of dicarboxylic acid with various number of carbon atoms. The effects of nature of various modifiers on mechanical properties of PEO were investigated. Among various dicarboxylic acid salts, half neutralized adipic acid (HNAA) is found to be highly effective in achieving the improvement in mechanical and dynamic mechanical properties due to improved dispersion of MWCNT in the PEO matrix. The physical interaction of HNAA with MWCNT (cation-π interaction) has been established using Fourier transform infrared and Raman spectroscopic analyses. Scanning electron microscope and transmission electron microscope (TEM) studies clearly indicate the improvement in the level of dispersion of MWCNT due to the addition of HNAA. Crystallization behavior of the PEO/MWCNT composites made with unmodified and modified MWCNT were studied by differential scanning colorimetry. Our approach is a noncovalent one and does not destroy the π-electron clouds of MWCNT as opposed to chemical functionalization techniques and particularly attractive because of possibility of preserving the structural integrity of nanotubes as well as improved phase adhesion with polymer matrix.