Elongational rheology of salt containing montmorillonite-PEO aqueous dispersions

PMSE 419

Eduard A. Stefanescu, estefa1@lsu.edu1, Ioan I. Negulescu, inegule@lsu.edu2, William H. Daly, chdaly@lsu.edu1, and S Petrovan3. (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) Department of Chemical Engineering, University of Tennessee, 419 Dougherty Hall, Knoxville, TN 37996
When passing a material through a semihyperbolic convergent die in an elongational rheometer, high degrees of order are induced in the material, and the entropy changes, indicative of orientation, can be calculated. In this work we are interested in determining the extent of internal orientation developed in salt containing Montmorillonite-poly(ethylene oxide) dispersions subjected to elongational deformations. We observe a strong shear thinning behavior of gels over the studied range of shear rates, with a linear relationship between viscosity and shear rate. Our results indicate that the size of the cation introduced in the system affects significantly the strength of the transient polymer-clay network, while the size and chemistry of the counter-ion may affect the orientational ability of clay particles and polymer chains.
 

Synthesis and Self-Assembly Approaches to Polymer-Inorganic Hybrid Nanoparticles
1:30 PM-4:10 PM, Wednesday, April 9, 2008 Hilton New Orleans Riverside -- Grand Salon 24, Oral

Division of Polymeric Materials: Science & Engineering

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