Grafting of polyaniline onto the radiation crosslinked chitosan

In this paper we report the chemical grafting of polyaniline onto the radiation crosslinked chitosan. Chitosan is crosslinked using 8 MeV electron beam and Co60 γ-ray in the presence of CCl4 as sensitizer. The so-obtained crosslinked chitosan is grafted with polyaniline (PANI) chemically using ammonium peroxy disulphate (APS) as an initiator. Grafted polymer is characterized by dissolution, swelling, UV–vis–NIR spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis, DC conductivity and nanoindentation studies. From the dissolution studies, grafting of PANI onto the crosslinked chitosan is confirmed. From the weight of films before and after grafting, grafting percentage is calculated. Grafting percentage increases as the monomer concentration increases and decreases with increase in crosslinking. This may be due to the decrease in the penetration of monomer onto the chitosan matrix with increase in crosslinking density. This is verified from SEM (cross-sectional view) of blend. UV–vis–NIR spectrum shows absorption peaks of PANI. Electrical property of grafted polymer is improved after doping with 1 M HCl. The change in volume conductivity is from 10−11 to 10−5 S/cm and surface conductivity from 10−10 to 10−2 S/cm. From TGA it is observed that grafted polymer and doped polymer are thermally stable.