Abstracto

Modification Of Carbohydrate Polymers Part 2: Grafting Of Methacrylamide Onto Pregelled Starch Using Vanadium-Mercaptosuccinic Acid Redox Pair

Kh.M.Mostafa, Abdul Rahim Samerkandy, A.A.El-Sanabary

Pregelled starch(PGS) as a reactive carbohydrate polymer has been chemically modified via graft co polymerization with methacrylamide(MAam) as a reactive monomer using vanadium-mercaptosuccinic acid redox pair as a new initiation system. This was done to maximize the graft yield and graft reaction efficiency percent and minimize the homopolymerization. The major factors affecting the polymerization reaction such as vanadium, mercaptosuccinic acid, MAam and sulphuric acid concentrations, liquor ratio as well as reaction time(duration) and temperatures have been studied systematically. The grafting parameters were studied with respect to graft yield and graft reaction efficiency percent as well as% homopolymerization. On the other hand, the newly prepared poly (MAam)-pregelled starch graft copolymers were characterized for heavy metal ions removal from their solutions. Based on the results obtained, appropriate conditions for grafting methacrylamide onto pregelled starch was established and the graft yield is higher under the following conditions: using 60 m mol/L Vanadium ion, 40 m mol/L mercaptosuccinic acid, 50mmol/L sulphuric acid; 50% methacrylamide concentration (based on weight of substrate), liquor ratio, 7.5, reaction time, 90 min; and polymerization temperature, 350C. Finally, the potential value of the resultant copolymers for heavy metal ion removal was assessed through measurements of critical properties such as removal of different heavy metal ions as well as durability.