XE-129 NMR AS A PROBE OF POLYMER BLENDS

The miscibility of two-component polymer blends has been investigated using xenon-129 (Xe-129) nuclear magnetic resonance (NMR) to probe the phase morphology. The chemical shift of Xe-129 dissolved in a given polymer is unique, thus heterogeneous blends with large domain sizes exhibit two Xe-129 NMR lines. When a single resonance is obtained, the data are consistent with miscibility, yielding an upper bound on the domain size. The temperature dependence of the relative solubilities and chemical shifts of Xe-129 dissolved in the pure components may allow a determination of the phase morphology in blends exhibiting a single resonance. The method is used to demonstrate that polychloroprene and 25% epoxidized 1,4-polyisoprene form a miscible blend.