Commercial cornstarch was alkenylsuccinylated with alkenylsuccinic anhydride to different degrees of substitution (DS) and then the products were graft-copolymerized with acrylic acid for investigating the effects of starch alkenylsuccinylation on the graft copolymerization with vinyl monomer, as well as on paste viscosity and film properties of alkenylsuccinylated starchg-poly(acrylic acid) (ASS-g-PAA). The number of carbon atom of alkenyl in alkenylsuccinates considered was 8 and 12, corresponding to octenylsuccinylation and dodecenylsuccinylation of starch, respectively. The graft copolymerization was accessed by grafting efficiency, grafting ratio, and conversion of monomer to polymer, and the film properties of ASS-g-PAA considered included tensile strength, breaking elongation, and work-to-break. Experimental results demonstrated that the alkenylsuccinylation showed marked effects on the copolymerization, paste viscosity, and film properties. It resulted in increased grafting efficiency, stable paste viscosity, and strong starch film. Carbon-chain length of the alkenyl and DS value of the alkenylsuccinates also exhibited evident effects on the copolymerization and film properties. Octenylsuccinylation of starch before the copolymerization was superior to dodecenylsuccinylation in improving the efficiency and film properties. Low levels of octenylsuccinylation could be utilized to increase the efficiency of the copolymerization and improve the properties of starch film.

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.