Chemical modification of MWCNTs with 5-aminoisophthalic acid and its effects on the thermal and morphological properties of chiral poly (ester-imide)/MWCNT nanocomposites having N-trimellitylimido-L-isoleucine moieties

In this article, carboxylated-multiwalled carbon nanotubes (MWCNT) s were functionalized with 5-aminoisophthalic acid under microwave irradiation conditions as a simple and efficient technique. Functionalized MWCNTs were incorporated into a chiral poly (ester-imide) (PEI) matrices using solution mixing and ultrasonic dispersion method. The optically active PEI was prepared by direct polycondensation reaction of chiral diacid with 4,4′-thiobis (2-tert-butyl-5-methylphenol) promoted by tosyl chloride in pyridine and N,N-dimethyl formamide solution. The nanocomposites (NC) s containing functionalized MWCNTs with loading levels of 5, 10, 15 wt.% were produced and studied in terms of morphology, thermal stability and chemical structure by X-ray diffraction, FT-IR spectroscopy, thermogravimetric analysis (TGA), transmission electron microscopy, and field emission scanning electron microscopy. It was found from TGA data that the NCs show improved thermal stability by comparison with the pure PEI as a result of uniform and efficient dispersion of functionalized MWCNTs in the PEI matrices. Microscopic observations indicated good filler dispersion and improved compatibility of the filler with polymer.