Superabsorbent hydrogels from poly(acrylamide-co-acrylonitrile) grafted Gum ghatti with salt, pH and temperature responsive properties

This research paper deals with the graft copolymerization of mixtures of acrylamide (AAm) and acrylonitrile (AN) with Gum ghatti (Gg) using ascorbic acid (ABC) and potassium persulphate (KPS) redox pair as an initiator and N,N’-methylene-bis-acrylamide (MBA) as an initiator via free radical graft copolymerization technique. Initially, effect of the various reaction parameters on graft copolymerization of Gum ghatti with AAm was studied and the effect of molar concentration of AAm-co-AN on water absorption capacity been investigated. Synthesized polymer was characterized by using different techniques like FTIR, SEM, XRD and TGA/DTA/DTG. Gg-cl-poly(AAm-co-AN) was found to be more crystalline and thermally more stable than Gum ghatti. Water absorption capacity of the candidate polymer was investigated in deionized water as a function of percentage swelling (Ps). Gg-cl-poly(AAm-co-AN) was found to show the maximum Ps of 921%. Effect of ionic strength and ionic charge of various cations on the Ps of candidate polymer in different chloride salt solutions (NaCl, BaCl2, FeCl3 and SnCl4) were investigated. It was observed that Ps decreased with increase in ionic strength and cationic charge

Author(s): Balbir Singh Kaith, Rajeev Jindal and Hemant Mittal

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