Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/12/2004
Publication Date: 10/18/2004
Citation: Parsons, J.D., Willett, J.L., Finkenstadt, V.L. 2004. Comparison of molecular weight of starch-graft-poly(acrylamide) produced by batch reaction and reactive extrusion [abstract]. American Chemical Society. p.196:435.
Technical Abstract: Free radical polymerization of acrylamide yields a bimodal molecular weight distribution for the homopolymer. Starch-graft-poly(acrylamide) shows the same behavior for grafted poly(acrylamide) chains. This distribution is seen in both batch reaction and reactive extrusion. Conversion of monomer for batch reaction was 45% with a grafting efficiency of 23% compared to 95% and 75%, respectively, for reactive extrusion. Compared to batch reactions which require more time and dilute solutions (2% total solids), reactive extrusion is more efficient with concentrated systems (50% total solids), fast grafting reactions and short residence times. Reactive extrusion allows continuous control of components such as initiator concentration, monomer ratios and starch feed rate. In addition, the combined effect of ingredient composition, mechanical and thermal energy allows for tuning of starch-graft-poly(acrylamide) composition and therefore its physical properties.