Preparation and characterization of starch-grafted multiwall carbon nanotube composites

A starch/carboxylated multiwall carbon nanotube (CCNT) composite (CCNT-starch) was prepared by covalently grafting a natural polymer starch onto the surfaces of CCNT. The obtained CCNT-starches were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-vis) and electrochemical measurement. FTIR revealed that the covalent bonds between -OH groups of soluble starch and CCNT were formed in CCNT-starch. TEM and TG showed that CCNTs were covered with the grafted starch about 7.7 and 12.8 wt% in CCNT-starch, respectively. The grafted starch facilitated the dispersion of CCNT-starch in water and chitosan films because of the hydrophilic polysaccharide structure of starch components. CCNT-starch containing 12.8 wt% starch in water could form homogeneous solutions without obvious aggregation of CCNTs. The electrochemical properties of the CCNT-starch were characterized by casting CCNT-starch and chitosan solution on glassy carbon electrode. Compared to CCNT, CCNT-starch exhibited a couple of redox peaks in cyclic voltammograms testing.