Synthesis of chitosan-g-aniline-crotonic acid: Optimization of processing parameters for efficient grafting using taguchi method

Abstract

Chitosan was chemically modified by grafting of aniline and crotonic acid onto the backbone of the chitosan using persulphate as initiator under inert nitrogen atmosphere. Chemical modification of chitosan was studied experimentally and optimized aiming to obtain highly efficient grafted polymer. To find out the optimum operating conditions that ensure the attaining of the modified chitosan with high grafting efficiency, four parameters were varied: concentration of chitosan, concentration of aniline, concentration of crotonic acid and amount of persulphate. The experiment was carried out on following Taguchi orthogonal array L9, and the best combination of factors was found using the desirability function approach. The optimization results showed that 0.1 g chitosan, 1.64 mol/L aniline, 1.77 mol/L crotonic acid and 0.14 mol/L persulphate leads to a chemically modified chitosan with efficient grafting percentage. Grafted copolymer (CS-g-An-CA) was characterised by UV–Visible spectroscopy, FTIR spectroscopy, X-ray diffraction and their thermal behaviour was studied using thermogravimetric analysis. The grafting parameters and the solubility of CS-g-An-CA were explored to have insight about the factors affecting the grafting efficiency. The water absorbency of the graft copolymer and their swelling kinetics were investigated to suggest the graft polymer for medical applications.