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.