ELASTOMERS AND PLASTICS Micro-Heterogeneity and Chain Mobility of blended Monodisperse Polymers

Polyisoprene (IR) and polybutadiene (BR) rubber with narrow molecular weight distribution are used to investigate the influence of chain length on blend behavior. For this purpose, dynamic-mechanical analysis and broadband dielectric relaxation spectroscopy are used. Blending BR and IR results in a homogeneous miscible system. 

Combining two different polymer types in one compound creates a so-called blend, whose material properties and viscoelastic response depend strongly on microstructure. When blended polymers are miscible, all polymer molecules are distributed randomly equally in space and form one homogeneous phase. In contrast for non-miscible polymers, a microscopic phase separation occurs. The main reason is the mismatch between both polymers A and B which is described by the interaction parameter χAB introduced by Flory and Huggins [1].