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Starch-poly(acrylamide-co-2-acrylamido-2-methylpropanesulfonic acid) graft copolymers prepared by reactive extrusion
- Willett, Julious L., Finkenstadt, Victoria L.
- J. APPL. POLYM. SCI. 2015 v.132 no.33
- acrylamides, composite polymers, ethanol, extruders, extrusion, gels, pH, polymerization, sodium chloride, starch, sulfonic acid
- Graft copolymers of starch with acrylamide and 2-acrylamido-2-methylpropanesulfonic acid (AMPS) were prepared by reactive extrusion in a twin-screw extruder. The weight ratio of total monomer to starch was fixed at 1 : 3, while the molar fraction of AMPS in the monomer feed ranged from 0 to 0.119. Monomer to polymer conversions were 85% or greater, with grafting efficiencies of 68% (highest AMPS content) to 85% (no AMPS). Absorbency in distilled water at pH 7 increased linearly with the mole fraction AMPS in the grafted polymer, while absorbencies in 0.9% NaCl were independent of AMPS content. When swollen in water/ethanol mixtures, swelling decreased gradually with increasing ethanol volume fraction, followed by a large decrease over a narrow ethanol concentration. This behavior is similar to that observed for AMPS-acrylamide gels. The swelling properties suggest these graft copolymers may have applications as responsive materials.