Novel route to synthesis of allyl starch and biodegradable hydrogel by copolymerizing allyl-modified starch with methacrylic acid and acrylamide

• Published in: Journal of polymer science. Part A, Polymer chemistry Polymer chemistry, 2003-06, Vol.41 (11), p.1650-1658
• Main Authors: Bhuniya, Sankar Prasad, Rahman, Safikur, Satyanand, Anshul J., Gharia, Mahendrasinh M., Dave, Ashok M.
• Format: Article
• Language: English
• Subjects: absorption capacity; allyl starch; Applied sciences; biodegradable; copolymerization; Exact sciences and technology; hydrogels; interfacial reaction; Natural polymers; Physicochemistry of polymers; Starch and polysaccharides; swelling
• ISSN: 0887-624X; 1099-0518
• DOI: 10.1002/pola.10711

Maize starch was modified by allyl chloride adopting an interfacial reaction technique with cetyltrimethyl ammonium bromide as a phase‐transfer catalyst and pyridine as an acid acceptor. The degree of substitution was determined from an increasing carbon content of the modified starch. The percentage of carbon and hydrogen of the allyl‐modified starch was estimated by elemental analysis (C, H, and N), and the product characterization was done through 1H NMR and 13C NMR analyses. The allyl‐modified starch was then copolymerized with methacrylic acid and a combination of methacrylic acid and acrylamide at 50 and 70 °C with potassium persulfate as an initiator. The copolymer thus formed swelled in distilled water after neutralization with sodium carbonate. The percentage of absorption capacity of the hydrogels was determined with distilled water and 0.9% NaCl solution. The highest percentage of absorption, 6500%, was achieved for the developed hydrogel containing allyl starch and acrylic monomer in a 1.7:1 w/w ratio and acrylic monomer, namely, methacrylic acid and acrylamide in a 3.2:1 w/w ratio. The study on biodegradability of the developed hydrogel showed that the hydrogel is degradable in the presence of diastase (amylase). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1650–1658, 2003 Maize starch under partially soluble state was reacted with allyl chloride interfacially in the presence of cetyltrimethyl ammonium bromide as a phase‐transfer catalyst and pyridine as an acid acceptor. Consequently allyl starch was formed after 24h reaction under room temperature. Then allyl starch was polymerized with methacrylic acid and optionally acrylamide at 50 °C for 10h and 70 °C for 6h in an aqueous medium using the 0.1% potassium persulfate as an initiator. The developed starch‐based crosslinked polymer was neutralized by sodium carbonate under wet conditions and finally a granular shaped neutral hydrogel was obtained after drying.