Environmentally friendly functionalization of multiwalled carbon nanotube using ascorbic acid and efficient dispersion in chiral poly(ester-imide) containing 4,4′-thiobis(2-tert-butyl-5-methylphenol) moiety: thermal and morphological studies

Abstract

Carboxylated multiwalled carbon nanotubes (MWCNTs) were functionalized with ascorbic acid under microwave irradiation conditions as a simple and efficient method and dispersed in a chial poly(ester-imide) (PEI) matrix using solution blending technique. Optically active PEI was prepared by a step-growth polymerization of amino acid-based diacid (3) with 4,4′-thiobis (2-tert-butyl-5-methylphenol) (4) promoted by tosyl chloride in pyridine and N,N-dimethyl formamide solution. The nanocomposites (NCs) containing different loadings of functionalized MWCNTs (5, 10, 15 wt%) were produced and characterized regarding to chemical structure, morphological, and thermal properties by X-ray diffraction, FT-IR spectroscopy, thermogravimetric analysis (TGA), transmission electron microscopy (TEM), and field emission scanning electron microscopy (FE-SEM). The TGA results showed that the introduction of modified MWCNTs improved the thermal stability of NCs compared to the neat PEI. TEM and FE-SEM images of the NCs revealed that the functionalized MWCNTs were dispersed uniformly and strongly interacted with the surrounding PEI matrix. The overview of these results is presented.