Structure/property relationships in polyurethane elastomers

Commercially available segmented poly(urethaneurea)s (SPUU) are high performance elastomeric materials utilized in a wide variety of applications. The unique properties of these materials results from their heterogeneous microphase structure which is composed of rigid and flexible domains. In order to fully assess the properties of these materials structure-function relationships were established utilizing solid state NMR and dynamic mechanical analysis.;The multiple motional frequencies inherent in polymer systems contribute to the physical measurements observed for these systems whether they be obtained on the microscopic or macroscopic level. Correlations have been developed for a series of diverse polymer systems and a series of similar polymer systems which relate the macroscopic properties of storage modulus (E;Spin-lattice relaxation time (T;The permeation phenomenon through SPUU's was studied in order to understand the mechanism of water transport through these materials and to determine the effect of water permeation on the microdomain morphology. These studies combined the NMR investigations of polymer chain dynamics with the macroscopic bulk polymer performance obtained via dynamic mechanical analysis, and a theoretical assessment of structural and energy changes obtained via molecular modeling studies.