PMSE 66 |
| Novel aqueous porous polyurethane dispersions are made by recently developed technology for producing nanostructured PUDs. The original patent-pending method is comprised of the preparation of two prepolymers with different hydrophilicities, which are mixed together before dispersing. To achieve porous morphology, we exploited the dramatic difference in reactivity between aliphatic and aromatic isocyanates. Thus, one prepolymer (core) was prepared with hydrophobic polyol and aromatic isocyanate. A second prepolymer (shell) was made from hydrophilic polyol and aliphatic isocyanate. After mixing the two prepolymers and dispersing the mixture in water, hydrophobic polyol pulled aromatic isocyanate groups to the center of the particle, where their hydrolysis generated CO2 gas, a blowing agent. The gas caused particles to bulge from within. The particle morphology was frozen by reacting remaining aliphatic isocyanate groups with a diamine extender. The in-situ generated CO2 is environmentally-friendly replacement for traditional blowing agents and the process is conducted in water. |
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Nano- and Micro-Scale Porous Polymer-Based Systems
1:25 PM-4:20 PM, Sunday, August 19, 2007 Westin Boston Waterfront -- Adams, Oral
Division of Polymeric Materials: Science & Engineering |