Poly starch

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))... 

Poly(starch-g-((l-amidoethylene)-co-(sodium 1-carboxylatoethylene))). Poly(l-amidoethylene) is, however, rarely used as a viscosifier. Instead, the homopolyraer is reacted with base (hydrolyzed with NaOH) to convert some of the amide units of the polymer to carboxylic acid units. The acid units on the hydrolyzed polymer dissociate in water and produce a polyanionic polymer. This polyelectrolyte expands in water because of ion-ion repulsion and, as an enlarged molecule, is a better viscosifier. 

Poly(starch-g-(l-amidoethylene)) copolymer is not a polyelectrolyte and will be a smaller molecule in water than an equal molecular weight, partially hydrolyzed poly(l-amidoethylene). Polyelectrolyte effect should, however, cause the graft copolymer to expand in solution in the same way it causes poly(l -amidoethylene) to expand, so a series of hydrolyzed graft copolymers were prepared from poly(starch-g-(l-amidoethylene))(41-43) and these derivatives were tested to determine the effect of hydrolysis on copolymer properties in solution. 

Figure 5. Screen factor of solutions of hydrolyzed poly(starch-g-(2 propenamide)) copolymer.

Poly(starch-g-((l-amidoethylene)-co-(sodium 1-(2-methylprop-2N-yl-1 -sulfonate)amidoethylene))). 

Poly(starch-g-(1-amidoethylene)) copolymers can be formed by ceric-ion- initiated, free-radical polymerization of 2-propenamide on starch. Poly(starch- g-[partially hydrolyzed 1-amidoethylene]) can be formed by treatment of an aqueous solution of the copolymer with 0.5 M sodium hydroxide at 40UC under anaerobic conditions. Treatment of the copolymer under these conditions for 10 minutes produces a hydrolyzed copolymer with a degree of hydrolysis between 9 5 and 14 5 percent. 

John J. Meister, Damodar R. Patil, Margaret C. Jewell, Kyle Krohn, Synthesis, Characterization, and Properties in Aqueous Solution of Poly(Starch-g- [(l-amidoethylene)-co-(sodium l-(2-methylprop-2N-yl-l-sulfonate)amidoethylene)]), Proceedings of the American Chemical Society Division of Polymeric Materials,... 

Poly( starch-g- ((1 -amidoe thylene )-CO-(1-sodium carboxylato)ethylene)))... 

Limiting viscosity number versus calculated molecular weight for samples of poly(starch-g-l-amidoethylene) with different numbers of sidechains in the molecule. 

Limiting Viscosity Number of Poly(starch-g-(l-amidoethylene)) Copolymers with... 

J.J. Meister, Linda (Mu Lan) Sha, Synthesis, Characterization, Properties, and Derivatives of Poly(Starch-g-(1-amidoethylene))-Copolymers, to be published by J. Appl. Poly. Sci., 1/87. 

---