Rheological behavior of laponite-montmorillonite hybrid dispersions containing poly(ethylene oxide)

POLY 113

Eduard A. Stefanescu, estefa1@lsu.edu1, Ioan I. Negulescu, inegule@lsu.edu2, William H. Daly, chdaly@lsu.edu1, and Gudrun Schmidt, gudrun@purdue.edu3. (1) Department of Chemistry, Louisiana State University, 232 Choppin Hall, Baton Rouge, LA 70803, (2) School of Human Ecology, Louisiana State University AgCenter, 143 Human Ecology Bldg, Tower Drive, Baton Rouge, LA 70803, (3) Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Drive, West Lafayette, IN 47907-2032
The objective of this contribution is to understand how the rheological properties of polymer based nanocomposite dispersions are influenced when two clays with different chemistries, sizes and surface areas are combined. The two clays that are used in this work are Laponite (LRD) and Montmorillonite (CNA). At very low concentrations, both LRD and CNA aqueous solutions show Newtonian behavior. However, in the presence of polymers, the interactions between the nanoparticles, as well as the interactions between polymer chains and the nanoparticles cause major changes in rheological behavior. Under shear, platelets orient and polymer chains stretch. We hypothesize that at high shear rates, where the PEO chains are fully stretched, the adsorption/desorption equilibrium is broken and desorption of chains from the platelets surface occurs at a higher rate than adsorption does.
 

Excellence in Graduate Polymer Science Research
6:00 PM-8:00 PM, Sunday, April 6, 2008 Morial Convention Center -- Hall A, Poster

Division of Polymer Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008