(236g) Modeling of Phase Behavior of Polymer Blends Containing Linear Telechelic Supramolecular Polymers

Polymer blending is an important route to obtaining new polymer materials that are easier to process and have tunable properties. We are studying a new class of polymer blends: traditional linear polymers blended with end-to-end associating supramolecular polymers. These hybrid systems are expected to exhibit unusual phase behavior since the size of the supramolecular component (virtual molecular weight) depends on temperature. A simple model is used to predict how the phase behavior of idealized polymer - (supramolecular polymer) binary blends differs from that of traditional polymer-polymer blends. Inputs to the model include the lengths of the unimers and polymers, the free energy of forming supramolecular bonds, and a Flory-Huggins interaction parameter. The model calculates the equilibrium degree of association for a pure supramolecular polymer and that of a mixture containing a supramolecular component and a monodisperse polymer. The free energy of mixing is calculated to determine whether the components are miscible. This exercise is repeated as a function of composition and temperature to construct phase diagrams. Resulting diagrams exhibit an upper critical solution temperature, though phase boundaries are asymmetric and the critical point is at a different location when compared to classical polymer-polymer blends. The results from our model have seeded an effort to experimentally verify predictions.