Submitted to: Bio Environmental Polymer Society
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/2003
Publication Date: 8/10/2003
Citation: Willett, J.L., Finkenstadt, V.L. 2003. Initiator effects in reactive extrusion of starch-polyacrylamide graft copolymers. Bio Environmental Polymer Society. p. 26.
Technical Abstract: We have recently demonstrated the use of reactive extrusion to produce starch-polyacrylamide graft copolymers. To ascertain the effects of free radical initiators on the properties of SGPs, we examined three initiating systems: ammonium persulfate (APS), ceric ammonium nitrate (CAN), and ferrous ammonium sulfate/hydrogen peroxide (FAS). Initiators were used at levels of 70, 140, and 280 anhydroglucose units/initiator, and starch/acrylamide ratios from 3:1 to 1.3:1. At all AGU/initiator levels and starch/AAm ratios, APS gave the highest monomer conversions (90%) and grafting efficiencies, while CAN gave low conversions (20%). Conversions using CAN were only slightly greater than the controls with no initiator. APS gave grafting efficiencies of 70% or greater, while efficiencies for CAN were only 20% to 30%. Increased monomer conversion was correlated with extrusion parameters, as materials extruded with APS gave die pressures and specific mechanical energy values significantly greater than CAN. In general, the properties of the FAS initiated polymerizations were somewhat less than those of APS, but significantly greater than CAN.