title: Two glass transitions in miscible polymer blends?
abstract: In contrast to mixtures of two small molecule fluids, miscible binary polymer blends often exhibit two structural relaxation times and two glass transition temperatures. Qualitative explanations postulate phenomenological models of local concentration enhancements due to chain connectivity in ideal, fully miscible systems. We develop a quantitative theory that explains qualitative trends in the dynamics of real miscible polymer blends which are never ideal mixtures. The theory is a synthesis of the lattice cluster theory of blend thermodynamics, the generalized entropy theory for glass-formation in polymer materials, and the Kirkwood-Buff theory for concentration fluctuations in binary mixtures.
authors.affiliation: The James Franck Institute and the Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Jacek
authors.initials: J
authors.lastname: Dudowicz
authors.affiliation: Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
authors.forename: Jack F
authors.initials: JF
authors.lastname: Douglas
authors.affiliation: The James Franck Institute and the Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Karl F
authors.initials: KF
authors.lastname: Freed