Submitted to: Society of Rheology
Publication Type: Abstract Only
Publication Acceptance Date: October 17, 1999
Publication Date: N/A
Technical Abstract: This research focuses on the flow behavior of highly starch-filled poly(hydroxyester ether) (PHEE) composites. In this paper effect of starch volume fraction on the composite viscosity is presented. Corn starch (Buffalo 3401)/PHEE (Dow Chemical) were extruded using Leistritz twin screw extruder with starch volume fractions from 0.27 to 0.66. The starch was dried to a moisture content of 0.7% to minimize moisture effect on composite rheology. Dynamic frequency sweep measurements were carried out using ARES Rheometer (Rheometric Scientific) at 120 deg C and 1% strain. The maximum packing fraction of the starch (in ethanol) was determined to be 0.61 with a Quanta Chrome Autotap. Starch volume fraction dependence of melt viscosity is well described using Maron & Pierce, Frankel & Acrivos, and Mooney equations when starch packing fraction is below the maximum packing fraction. Reasons are discussed for the deviation of composite viscosity from the models and extrusion processability of the composite at starch volume fraction above the maximum packing fraction. This research was conducted under CRADA 58-3K95-8-0635 between the Agricultural Research Service and Biotechnology Research and Development Corporation.