Grafting of poly(vinyl acetate) to granular corn starch

Abstract

SynopsisVinyl acetate forms graft copolymer with granular corn starch when initiated by peroxide plus activator in an aqueous slurry of the starch. Grafting efficiencies are less than 50%, much lower than realized with either acrylonitrile or methyl methacrylate under comparable conditions. Grafting efficiency can be raised by including with the vinyl acetate a minor amount of comonomer. Among the comonomers used, methacrylic acid and methyl methacrylate were particularly effective for increasing the grafting of vinyl acetate.

Graft copolymerization of acrylamide onto cellulose in presence of comonomer using ceric ammonium nitrate as initiator

“…The graft copolymerization of acrylamide in presence of ethylmethacrylate has shown a substantial increase in graft yield (% G Y ) in comparison with graft yield (% G Y ) found with individual acrylamide. Because of the synergistic effect of ethylmethacrylate on acrylamide, the extent of overall grafting has also increased considerably 26. Because of strong interactions between acrylamide and ethylmethacrylate, the chains grafted onto cellulose were purely copolymeric in nature, which has provided a strong support that grafting of individual monomer in presence of comonomer was inhibited in present system.…”

Controlled Release of Urea Encapsulated by Starch-g-poly(vinyl acetate)

“…Because of the hydrolytic action of acetyl in acid hydrolysis of the starch graft copolymer, the weight method for measuring the weight of the grafted PVAc after acid hydrolysis would not be very accurate. Therefore, we employed a bromination method to titrate the amounts of residual VAc monomer when the graft copolymerization was just completed …”