Agar/sodium alginate-<i>graft</i>-polyacrylonitrile, a stable hydrogel system

Abstract

Polyacrylonitrile grafted agar/sodium alginate (Agar/Na-Alg-<i style="">graft</i>-PAN) has been synthesized in aqueous medium under reflux conditions in the presence of potassium persulphate as a free radical initiator. By varying the reaction parameters, e.g., concentrations of acrylonitrile monomer and K₂S₂O₈, reaction time and temperature, the optimum grafting conditions have been identified as that having the highest grafting ratio (Gr 1.87), total conversion (Ct 1.05) and grafting efficiency (Ge 0.89). The blend and grafted products have been characterized by FT-IR, X-ray diffraction, differential scanning calorimeter and scanning electron microscopy. The swelling capacity of Agar/Na-Alg-<i>graft</i>-PAN is found to be 8.5g/g at <i style="">p</i>H 1.2 and the swelled material is stable for over 24 h. This copolymer hydrogel system may be exploited in various applications utilizing its swelling properties and stability.