Graft copolymerization of granular starch maleate with acrylamide for enhancing grafting efficiency

Abstract

Graft copolymerization of granular starch maleate with acrylamide using Fenton ' s initiator in aqueous dispersion was investigated for increasing grafting effi ciency of the copolymerization. The graft copolymerization was characterized in terms of grafting effi ciency, grafting ratio, and conversion of monomer to polymer. Effects of maleate modifi cation of starch on the effi ciency, ratio, and conversion were explored. Infl uences of reaction variables such as pH value, molar ratio of H 2 O 2 to Fe 2 + , initiator concentration, monomer concentration, polymerization temperature, and time on the copolymerization were investigated. It was observed that the modifi cation of starch markedly increased grafting effi ciency and ratio. The graft copolymerization should be carried out under the protection of nitrogen gas at 30 ° C -45 ° C for 3 h using H 2 O 2 /Fe(NH 4 ) 2 (SO 4 ) 2 as initiator. Preferred molar ratio of H 2 O 2 /Fe(NH 4 ) 2 (SO 4 ) 2 /anhydroglucose was 20:1:1000 and optimal value of pH was in a range of 3 -4. The condition could make grafting effi ciency and conversion of monomer to polymer higher than 65 % and 95 % , respectively.