SMALL-ANGLE NEUTRON-SCATTERING AND LIGHT-SCATTERING-STUDIES ON THE MISCIBILITY OF PROTONATED POLYISOPRENE DEUTERATED POLYBUTADIENE BLENDS

Binary mixtures of protonated polyisoprene and deuterated polybutadiene with particular microstructures exhibit an LCST-type phase behavior. Small-angle neutron scattering (SANS) and time-resolved small-angle light scattering (SALS) techniques were employed to study the static and dynamic phase behavior of the mixtures. From the static study by SANS, binary interaction parameters, chi, and the phase diagram were obtained. The spinodal temperature at the critical blend composition obtained by the analysis of SANS profiles from the single-phase state was in good agreement with that obtained by the time-resolved SALS measurements. The component polymers are prepared by living anionic polymerization and hence have well-defined molecular characteristics. Therefore, this system is considered to be an excellent polymer mixture system for the study of the relationships between static and dynamic phase behaviors of the polymer mixture and the molecular parameters such as molecular weight, polydispersity, microstructure, etc.