Reactive Extrusion of Starch–Polyacrylamide Graft Copolymers Using Various Starches
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Graft copolymers of polyacrylamide and various substrates were prepared by reactive extrusion in a twin screw extruder using ammonium persulfate as initiator. Substrates included unmodified starches (corn, waxy maize, wheat, and potato), cationic starches, dextrin, dextran, and polyvinyl alcohol (PVOH). The feed ratio of substrate to monomer was 2:1. Average conversion of monomer to polymer was 88.9% (±5.1%). Graft contents for the starch substrates were approximately 25% with grafting efficiencies of about 70%. Polyacrylamide graft molecular weights ranged from 317,000 to 769,000. Absorbencies at pH 7 for saponified graft copolymers prepared with unmodified starches were approximately 200 g/g and approximately 150 g/g for the cationic starches, dextran, and PVOH. In electrolyte solution (0.9% NaCl), absorbencies were in the range of 26–59 g/g, depending on substrate type. Saponified dextrin copolymers were essentially soluble with absorbencies of 6 g/g in water and 12 g/g in 0.9% NaCl.
KeywordsStarch Graft copolymer Reactive extrusion Polyacrylamide
The authors gratefully acknowledge the contributions of B. Jasberg, G. Grose, K. Hornback, and R. Haig to this work.
- 1.Weaver MO, Bagley EB, Fanta GF Doane WM (1974) Appl Polym Symp 25:97Google Scholar
- 2.Weaver MO, Bagley EB, Fanta GF, Doane WM (1976) U.S. Patent 3,935,099Google Scholar
- 3.Fanta GF, Doane WM (1977) U.S. Patent 4,045,387Google Scholar
- 5.Fanta GF, Stout EI, Doane WM (1980) US Patent 4,194,998Google Scholar
- 6.Antholz P, Swarthout EJ (1980) U.S. Patent 4,221,684Google Scholar
- 10.Fanta GF (1996) Polymeric Materials Encyclopedia 10:7901Google Scholar
- 12.Carr ME, Kim S, Yoon KJ, Stanley KD (1992) Cer Chem 69:70Google Scholar