Novel Miscible Polymer Blend of Poly(4-trimethylsilylstyrene) and Polyisoprene

The phase behavior of the newly found miscible polymer blends poly(4-trimethylsilylstyrene) and polyisoprene was investigated with optical microscopy (OM) and also with differential scanning calorimetry (DSC), while the degree of polymer−polymer interaction was evaluated with small-angle neutron scattering (SANS). The blends with homogeneous one phase at various compositions turned into two phases by heating, showing a lower critical solution temperature (LCST) type phase diagram with a critical temperature of 172 °C if the degree of polymerization is ca. 370. The blend gave a single glass transition temperature below the LCST, and the interaction parameter χ was represented as a function of temperature T according to the relationship χ = 0.027 − 9.5/T.