Main content area

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.