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Compatibility in Blends of Two Random Copolymers Having a Common Monomer Segment
Macromolecules (1986)
  • William MacKnight, University of Massachusetts Amherst
  • Tomoo Shiomi
  • F. E. Karasz
Miscibility in blends of random copolymers (A.,B1-:r),.,_ and (CyB1-y)111 can conveniently be displayed as domains in a Cartesian coordinate system in which the abscissa and ordinate represent the compositions of the respective copolymers. For the case in which the two copolymers have a common monomer unit (e.g., B) the isothermal boundary between domains of miscibility and immiscibility in a mean field treatment is determined by three segmental interaction parameters, XAB, XAC, and XBC, and the degrees of polymerization r1 and r2 of the copolymers. We have termed such representations "miscibility maps". The shape and size of the miscibility domain are determined by the relationships between these parameters, and the present study considers the various theoretical possibilities with interpretations based on intersegmental repulsion and/ or attraction. In addition, two experimental miscibility maps for blends of poly(vinyl chloride-co-vinyl acetate) with chlorinated poly(vinyl chloride) (regarded here as a random copolymer of vinyl chloride and 1,2-di­chloroethylene units) and poly(vinyl chloride-co-vinyl acetate) with poly(ethylene-co-vinyl acetate) were constructed by using as a criterion of miscibility the glass transition temperatures determined by scanning calorimetry. The boundary deiming the region of miscibility for the blend of poly(vinyl chloride-co-vinyl acetate) with chlorinated poly(vinyl chloride) was elliptical and that for the poly(vinyl chloride-co-vinyl acetate) /poly(ethylene-co-vinyl acetate) blend was defined by a pair of hyperbolas. Segmental interaction parameters between the different monomer units were estimated from these data and good correlation was obtained between theoretical evaluations and experiment. In addition the experimental miscibility map obtained by Hall et al. for blends of poly(styrene-co-maleic anhydride) with poly(styrene-co-acrylonitrile) was compared to the theoretical calculations.
  • Compatibility,
  • Blends,
  • Random,
  • Copolymers,
  • Common Monomer,
  • Segment
Publication Date
Citation Information
William MacKnight, Tomoo Shiomi and F. E. Karasz. "Compatibility in Blends of Two Random Copolymers Having a Common Monomer Segment" Macromolecules Vol. 19 Iss. 8 (1986) p. 2274 - 2280
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