MOLECULAR THERMODYNAMICS OF POLYMER COMPATIBILITY - EFFECT OF CONTACT AGILITY

While the influence of interaction energy on polymer-polymer compatibility has long been recognized, little explicit attention has been given to the influence of “structural effects”, i.e., of component contact agility, c/q. Calculated phase equilibria are shown for some polymer-polymer and some polymer-polymer-solvent systems using a perturbed-hard-chain theory. This theory predicts an LCST-type phase diagram for a polymer-polymer binary mixture when the contact agilities for polymers are different even though all energy parameters are identical. For ternary systems containing two polymers and a common solvent, solvent contact agility affects the compatibility differently in the UCST and the LCST region. When solvent contact agility is within a good solvent limit, so that the polymer-solvent binary is completely miscible, the lower contact-agility solvent is more efficient in the LCST region; however, the opposite holds in the UCST region. © 1979, American Chemical Society. All rights reserved.