Synthesis, characterization, and properties in aqueous solution of poly(starch-g-[1-amido-ethylene)-co-(sodium 1-(2-methylprop-2N-yl-1-sulfonate)amidoethylene)])

✍ Scribed by John J. Meister; Damodar R. Patil; Margaret C. Jewell; Kyle Krohn

• Publisher: John Wiley and Sons
• Year: 1987
• Tongue: English
• Weight: 981 KB
• Volume: 33
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1987.070330603

✦ Synopsis

Graft teqmlymem of starch, 2-propenamide, and sodium 2-methyl-3-imino-4-oxohex-5-ene-lsulfonate can be made by cerium-IV-initiated, free-radical polymerization of an aqueous monomer mixture on starch. Synthesis is conducted on aqueous, gelled, lintnerized potato starch at 30°C under a nitrogen atmosphere. Yields range from 50 to 100 wt % and products contain 9-52 wt % starch, 1-51 w t % 1-acidoethylene, and 18-65 wt % sodium 1-(2-methylprop-2N-yZ-lsulfonate)amidoethylene. %peat unit ratios in the reaction product approximate monomer ratios in the reaction mixture. F'raction of starch grafted in a reaction decreases as the mole fraction of sulfonated monomer in the reaction mixture increases. No proof has been found for grafting of synthetic side chains to starch in monomer mixtures containing only sulfonated monomer. Starch graft copolymers with side chains composed of 1-amidoethylene units and a sulfonated 1amidoethylene unit derivative, 1-(sodi~2-methylprop-2N-yZ-l-sulfonate])amidoethylene, are water-soluble, thickening agents. The rheology of solutions of these copolymers is a function of the ratio of nonsulfonated to sulfonated repeat units in the synthetic chains of the molecule. Aqueous solutions of these products are shear thinning and have power law exponents which decrease 1) with increasing product concentration or 2) as the nonsulfonated to sulfonated repeat unit ratio move8 toward 3/1. Limiting viscosity number of product in water decreases with increasing shear rate of measurement or with increasing salt concentration of the solvent. Formulas are derived from the theories of Kirkwood and Flory which show that for copolymers with constant molecular weight, expansion coe5cient, and limiting viscosity number increase as the fraction of sulfonate-containing repeat units in the chain increase. This theoretical requirement and the limiting viscwity data for groups of samples prepared under identical synthesis conditions are used to show that molecular weight of the graft copolymer decreases as the fraction of sulfonated repeat units in the copolymer increases. Screen factor measurements show product solutions to be viscoelastic.