Graft polymerization of starch

Cerium(IV) salts are used to initiate graft polymerization of starch. In order to graft-copolymerize starch, a complex of Ce(IV) was prepared by blending cornstarch with Ce(NH4)2(N03)6-HN03 reagent in the ratio of 75 glucose residues per Ce(IV) component.648 649... 

Schroder, U., Lager, C., and Norrlow, O., Carbo-lactic microspheres Graft polymerization of PLA to starch microspheres, Proc. Int. Control. Rel. Bioact. Mater.. 14, 238,... 

Strongly anionic, highly water-soluble, graft copolymers of starch can be made by adding 2-propenamide and sodium 2,2-dimethyl-3-imino-4-oxohex-5-ene-1-sulfonate (Na DMIH) to the polymerization reactions. See references 43 and 56 for a discussion of these polymers. 

AASO3H does not graft polymerize onto starch as readily as acrylonitrile, and Table VI shows that both % add-on and % conversion increase with decreasing percentages of AASO3H in the monomer mixture. Conversion of monomers to polymer is over 90% with monomer mixtures oontcdning about 1 mole % AASO3H or less. 

Anionic graft-polymerization of paraformaldehyde onto starch and dextrin has been effected in methyl sulfoxide solution, polymerization being initiated by the carbohydrate potassium alcoholate formed from the reaction of the carbohydrate with naphthalene potassium, a metallation procedure not previously described for carbohydrates.220... 

Cerium(lV) compounds with suitable reducing agents, readily initiate the redox polymerization of, for example, vinyl monomers [22]. This property is used to initiate graft polymerization of vinyl monomers onto cellulose, wool, starch, cotton, etc. in order to, e.g. improve mechanical strength, resist moisture penetration and reduce micro-organism attack. 

Avery creative application of the system HRP/H202/Acac for graft polymerization of acryl amide on starch was reported recently by Biswas and coworkers [39], Thus, a biocatalytic alternative route to the established cerium( IV)-based routes to poly(acrylate)-grafted starch with applications as superabsorbers [44] or performance additives in paper making [45] or textile sizing [46] was reported. Under non-optimized conditions grafting efficiencies of up to 65% are reported. The... 

Athawale, V.D., Rathi, S.C., (1997), Effect of chain length of the alkyl group of alkyl methacrylates on graft polymerization onto starch using ceric ammonium nitrate as initiator. European Polymer Journal, vol. 33, No. 7, 0uly 1997), pp 1067-1071, ISSN... 

Mostafa, M., Graft polymerization of methacrylic acid on starch and hydrolyzed starches. Polymer Degradation and Stability, (1995), Vol. 50, No. 2, (March 1995), pp 189-194, ISSN 0141-3910. 

A lower graft molecular weight and more frequent grafting usually results from anionically initiated graft copolymerization. Zilkha et al. initiated graft polymerization of ethylene and propylene oxides with alkali metal oxides of starch. Their... 

Coni, M. Gurruchaga, M. Valero and G.-M. Guzman, Graft polymerization of acrylic monomers onto starch fractions. I. Effect of reaction time on grafting methyl methacrylate onto amylose,/. Polym. Sci. Al, 21 (8) 2573-2580,1983. 

Fanta GF, Felker FC, Saleh JH. 2003. Graft polymerization of acrylonitrile onto starch-coated polyethylene film surfaces. J Appl Polym Sci 89 3323-3328. 

Etherification and esterification of hydroxyl groups produce derivatives, some of which are produced commercially. Derivatives may also be obtained by graft polymerization wherein free radicals, initiated on the starch backbone by ceric ion or irradiation, react with monomers such as vinyl or acrylyl derivatives. A number of such copolymers have been prepared and evaluated in extmsion processing (49). A starch—acrylonitrile graft copolymer has been patented (50) which rapidly absorbs many hundred times its weight in water and has potential appHcations in disposable diapers and medical suppHes. 

A large number of SAHs described in the literature combine synthetic and natural macromolecules in the network structure. The natural components are usually starch, cellulose, and their derivatives. It is assumed that introduction of rigid chains can improve mechanical properties (strength, elasticity) of SAH in the swollen state. Radical graft polymerization is one of the ways to obtain such SAH. 

A unique method of formulating delivery systems based on starch/ PLA systems was studied (138). In that approach, the goal was to provide a better matrix for delivery of high molecular weight hydrophilic molecules. A hydrophilic material, starch, was combined through graft polymerization to PLA. The carbolactic polymers were then used to entrap bovine serum albumin in microspheres. 

Synthesis. Graft copolymer was formed in aqueous solution by ceric-ion-initiated, radical polymerization of monomer on starch. Polymerization was conducted in an inert, atmosphere. Details of the synthesis procedure may be found in references 41 to 43 In recovering the polymer product, freeze drying was used with care since freeze drying produces a more dissolvable and useful product but can degrade polymers with molecular weights of 1 million or more. Poly(starch-g-(1-amidoethylene)) Poly(starch-g-(1-amidoethylene))... 

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