POLY 28 |
| The rheological evaluation and molecular interpretation of microgel systems are assisted by scaling theories that have been developed to explain the role of hydrophobic °„multistickers°„on the formation of gel networks by polyelectrolytes. We have applied these theories to hydrophobically-modified polyelectrolyte thickeners. We have generated plots of reduced specific viscosity against polymer concentration for microgel thickeners and hydrophobically-modified microgel thickeners. The intrinsic viscosity, [Ų], is a measure of the hydrodynamic volume of the polymer microgel in solution. Our results show that these cross-linked polyacrylates exist as isolated molecules in dilute solution. C* is distinct and for both of these polymers it is essentially identical to the Einstein theoretical value for non-interacting spheres. The intrinsic viscosities for these polymers are 10 dl/g and 25 dl/g respectively. However, the scaling above C* is 40 and 13 for these polymers and this would be consistent with a higher shear modulus. |
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Undergraduate Research in Polymer Science
8:15 AM-12:00 PM, Sunday, April 6, 2008 Hilton New Orleans Riverside -- Grand Salon 16, Oral
Division of Polymer Chemistry |