Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/29/2004
Publication Date: 12/5/2004
Citation: Chiou, B., Yee, E., Shey, J., Glenn, G.M., Wood, D.F., Orts, W.J. 2004. Properties and processing of starch-based nanocomposites containing nanoclays. BioEnvironmental Polymer Society International Meeting in Monterrey, Mexico, December 5-10, 2004. Paper No. 17 (Abstract).
Technical Abstract: We produced starch-based nanocomposites by extruding native wheat starch with montmorillonite nanoclays using a twin-screw extruder. We first examined the rheological properties of wheat starch with various hydrophilic and hydrophobic nanoclays. The samples containing 5 wt. % or greater concentration of the most hydrophilic nanoclay, Cloisite Na+, exhibited gel-like behavior at room temperature. When we heated the nanoclay samples to 95°C, the Closite Na+ samples had the highest elastic modulus after gelatinization. These rheological data indicated that wheat starch had more interactions with Cloisite Na+ than the other more hydrophobic nanoclays. We then examined the effects of moisture content, screw speed, and temperature on nanoclay dispersion during extrusion. For Cloisite Na+ samples, moisture content had the greatest effect. Using x-ray diffraction, we found no Cloisite Na+ diffraction peaks for the high moisture samples, indicating possible exfoliation of nanoclay. In contrast, for the more hydrophobic Cloisite 30B clay samples, moisture content and screw speed had no effect on nanoclay dispersion. Only an increase in temperature produced intercalation of the Cloisite 30B samples. The Cloisite Na+ extrudates showed improved water resistance as well as improved mechanical properties.