Chemical and Electrochemical Grafting of Polyaniline onto Chitosan

Conductive polymers are good candidates for preparation of conducting graft copolymers. Therefore, polyaniline was chemically grafted onto chitosan by using ammonium peroxydisulphate initiator, in the presence of 1 M HCl to obtain a product known as Chitaline (chit-g-PANi). Electrochemical polymerization was carried out by coating chitosan on the surface of Pt disk working electrode. Then, PANi grew onto chitosan in acidic solution and a graft copolymer was produced. The grafted copolymer was identified by FTIR, UV-visible, and 1H and 13C NMR spectroscopy techniques. Spectroscopic studies show the grafting and demonstrate that the electronic states are similar to those of the emeraldine and protonically doped emeraldine forms of polyaniline. The thermal properties of chit-g-PANi were studied by thermogravimetric (TGA) and differential scanning calorimetry (DSC). Morphology properties of chit-g-PANi have been studied by SEM images which confirm grafting polymerization. The effects of concentration of APS, ANi, reaction time and temperature on graft copolymerization were studied by determining the grafting percentage, grafting efficiency and percentage add-on. Electrical conductivity of copolymer has been studied by four-point probe method of having produced 4.6×10-2 S/cm conductivity.