Starch graft copolymerization

Base polymer Starch—graft copolymerization, carboxymethylation Cellulose—graft copolymerization, carboxymethylation Synthetic polymers—poly(acrylate), poly(vinyl alcohol), poly(acrylamide), poly(oxyethylene), cationic polymer... 

PS/starch graft copolymerization ICRR Two-step mechanism kinetics de Graaf and Janssen 2000... 

Although they lack commercial importance, many other poly(vinyl acetal)s have been synthesized. These include acetals made from vinyl acetate copolymerized with ethylene (43—46), propjiene (47), isobutjiene (47), acrylonitrile (48), acrolein (49), acrylates (50,47), aHyl ether (51), divinyl ether (52), maleates (53,54), vinyl chloride (55), diaHyl phthalate (56), and starch (graft copolymer) (47). 

Recently, Li et al. [30], Yu et al. [31] reinvestigated the mechanism of graft copolymerization of vinyl monomers onto carbohydrates such as starch and cellulose initiated by the Ce(IV) ion with some new results as mentioned in Section II. Furthermore, they investigated the mechanism of model graft copolymerization of vinyl monomers onto chitosan [51]. They chose the compounds containing adjacent hydroxyl-amine structures, such as D-glucosamine, /mn5-2-amino-cyclohexanol, 2-... 

How could you use graft copolymerization techniques to reduce the water solubility of starch ... 

Athawale, V. D., Lele, V. (1998). Graft copolymerization onto starch. II. Grafting of acrylic acid and preparation of its hydrogels. Carbohydrate Polymers, 35,21-27. 

Fu, Z. S., Liang, W. D., Yang, A. M., Wang, Z. G. (2002). Role and relevance of polarity and hindrance of vinyl monomers in graft copolymerization onto potato starch. Journal of Applied Polymer Science, 85, 896-899. 

Manganic ions (Mn +) in aqueous solution have been developed in our laboratories as an initiator for grafting vinyl monomers onto various polysaccharides, e.g. starch (1), cellulose (2) and guaran (3). This research is part of a general program on graft copolymerization onto polysaccharide substrates as described in a review paper (4). The Mn "1" grafting method has been applied as... 

B. Ranby, "New Methods for Graft Copolymerization onto Cellulose and Starch", in "Modified Cellulosics" (Eds. R.M. Rowell and R.A- Young), Acad. Press, New York 1978 p. 171-195. 

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... 

Reaction conditions necessary to carry out the modifications described earlier in this section usually result in some decomposition of amylose and amylopectin, even when simple substitution, addition, or crosslinking are involved. As a rule, graft copolymerization produces derivatives of significantly increased molecular weight. Starch grafting usually entails etherification, acetalation, or esterification of starch with vinyl monomers to introduce a reaction site for the further formation of a copolymeric chain. Such a chain would typically consist of either identical or different vinyl monomers (block polymers), or it may be grafted onto another polymer altogether. 

Aluminoxanes suppressed side reactions involving hydrogen transfer. They also formed cyclic structures with starch, giving copolymers that were coated with crystalline polyethylene. A catalyst composed of dicyclopentadienylzirconium dichloride and trimethylaluminium permitted polymerization of ethylene on starch in a toluene suspension at 60 °C for 2h.2806 Graft copolymerization of methyl methacrylate onto starch was also performed with an acetylacetone-copper(II) complex in trichloroacetic acid.2807 The grafting yield and efficiency were proportional to the initiator concentration up to 7.0 x 10-3 mole/L. 

The degree of swelling of the synthetic gel in distilled water was 21 the degree of swelling in the saponified graft-copolymerization state with starch was 50. 

Lightly cross-linked polyacrylamide is used to make superabsorbents of water. Astarch-g-polyacryla-mide/clay superabsorbent composite has been synthesized [27] by graft copolymerization reaction of acrylamide, potato starch, and kaolinite micropowder (< 1 pm) followed by hydrolysis with sodium hydroxide. Such a superabsorbent of compositin 20% kaolinite, 20% potato starch, 60% acrylamide, 2% initiator (ceric amonium nitrate), and 0.04% cross-linker (N,N-methylenebisacrylamide) is found to absorb 2250 g H20/g at room temperature at swelling equilibrium. 

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