Preparation And Characterization Of Polysaccharide-grafted Multiwall Carbon Nanotube Composites

Carbon nanotubes (CNTs) have received much attention because they were found to be promising as a nanoscale material for a variety of potential applications such as electronic, optical, biosensor and biomedical and so on. Usually, CNTs are bunded, and not solubilized in almost any solvents, which hampered their applications. It is desirable to modify the hydration properties of the surfaces of CNTs so that they become hydrophilic.In this paper, a novel method was used to prepare hydrophilic CNTs through covalently grafting biopolymers (soluble starch and guar gum) onto the surfaces of CNTs. UV-vis spectroscopy shows the absorption peak at about265nm. The intensity of absorbance at265nm in biopolymers-CNTs solutions was dependent on the solution concentrations in the linear fashion obeying the Lambert-Beer’s law. FTIR spectra indicated that the biopolymers are covalently grafted onto the CNTs. TEM images showed that the CNTs were covered by polymer chains and formed a core-shell structure.Since starch and chitosan are natural polysaccharides, CCNT and CCNT-starch were blended with chitosan to form modified electrodes to evaluate the effect of the grafted starch on the conductivity and the dispersion of CCNT-starch in polysaccharide films. The CCNT-starch B (the grafted starch about12.8%) modified electrode displayed a linear relation to glucose concentration range from0.01to10mM. Furthermore, in order to study the adsorption capacity of CNTs, iron oxide nanoparticles were synthesized on the MWCNT-GG to prepare the magnetic MWCNT-GG-Fe3O4, because magnetic CNTs are easy to operate in practical applications. TEM and X-ray analysis indicated that guar gum also assisted iron oxide nanoparticales to disperse on the CNTs surface due to the supramolecular interaction between the metal ions and hydroxyl groups of guar gum. The adsorption behavior of MWCNT-GG-Fe3O4for MB and NR could be described well by the pseudo second-order model. The adsorption isotherm experiments revealed that the adsorption data fitted Langmuir isotherm model.