Effect of Partial Saturation on Thermodynamic Interactions in Polydiene/Polyolefin Blends

Polymer blends exhibit properties that are highly dependent on interactions between components, typically quantified by the Flory-Huggins interaction parameter, χ. Polyolefins and polydienes are important materials with commercial relevance in elastomer applications. The majority of previous studies on the thermodynamics in polyolefin and polydiene systems have focused on polymer pairs within the same class, which generally exhibit a small and weakly temperature dependent χ. There is little quantitative information on thermodynamic interactions of polydienes and polyolefins. In our previous work, we characterized the χ parameter in a model polydiene/polyolefin blend based on 1,2-polybutadiene (1,2-PBD) by small angle neutron scattering (SANS). We observed an unusually large χ parameter in blends of 1,2-PBD and saturated 1,2-PBD that exhibited a strong temperature dependence. We also studied the impact of partial saturation on χ of polydiene/polyolefin blends. The χ(T) behavior in blends of fully saturated 1,2-PBD with partially saturated 1,2-PBD, at varying levels of saturation, was characterized. The applicability of the random copolymer theory to predict χ(T) behavior in these blends was evaluated.