Thermodynamic interaction parameter of star–star polybutadiene blends

Abstract

Abstract The value of the thermodynamic interaction parameter, χ eff , for star–star polybutadiene blends was determined with small‐angle neutron scattering. Blends in which the stars have the same number of arms and blends in which the stars have different numbers of arms are investigated. For star–star isotopic blends with components having the same number of arms, the presence of the junction point of the star leads to a value of χ eff that is larger than that for an analogous linear–linear isotopic blend. However, changes in the value of χ eff resulting from small dissimilarities in the number of arms of the two components in the isotopic star–star blends were too small to resolve. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 247–257, 2003