The generalized entropy theory of glass formation in binary polymer blends is a synthesis of (a) the lattice cluster theory for the thermodynamics of polymer mixtures, (b) the Adam-Gibbs relationship between the structural relaxation time and the configurational entropy density of a fluid, and (c) the rigorous Kirkwood-Buff theory for local concentration fluctuations in binary mixtures. The resulting approach is supplemented with the random phase approximation to determine the square gradient coefficient in the free energy expansion (about the critical point)which is crucial for evaluating the correlation length in binary compressible polymer mixtures, and with expressions for the temperature dependence of the radius of gyration for semiflexible, non-self-reversing lattice polymers to determine the radius of gyration for the components of the blend. The resultant, technically complicated theoretical tool predicts two structural relaxation times (and generally two glass transition temperatures) for miscible polymer blends. Qualitative comparison is made with experiments of Ediger and coworkers (Macromolecules 2003, 36, 1724) for the structural relaxation of PEO/PMMA blends.Supported by US Department of Energy, Office of Basic Energy, Division of Materials Science and Engineering, Award DE-SC0008631.

Glass-formation in miscible binary polymer blends

248th National Meeting (2014)

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