BLENDS OF CRYSTALLIZABLE POLYBUTADIENE ISOMERS

Precipitated blends of two crystallizable polybutadiene (PBD) isomers were characterized in terms of crystallization and phase behavior, mor phology, and tensile mechanical properties. The isomers are syndiotact ic 1,2 PBD (M(upsilon) = 32.5 kg/mol) and trans 1,4 PBD (M(upsilon) = 425 kg/mol). The blends exhibit heterogeneous behavior over the full r ange of composition. Using a solvent precipitation method, blends are obtained with heterogeneity on the order of 1 mum. Tensile properties of these semicrystalline blends are generally intermediate between tho se of the corresponding semicrystalline homopolymers, with some enhanc ement at approximately 10% 1,2 PBD content. Comparisons are made with previously reported data on amorphous PBD blends.