Crystallization and solid-state structure of model poly(ethylene oxide) blends

This paper presents an overview of several studies whose overall goal is to elucidate the solid state microstructure and crystallization kinetics of melt-miscible polymer blends. Model blends were prepared with poly(ethylene oxide) and four amorphous polymer diluents: two exhibiting relatively weak intermolecular interactions with PEO and two exhibiting strong interactions. Small-angle x-ray scattering experiments showed that the introduction of strong intermolecular interactions promoted diluent segregation over relatively large length scales, regardless of diluent mobility at the crystallization temperature. In addition, at a given T_c, spherulitic growth rates for blends with the strongly interacting polymers are considerably lower than those with weakly interacting polymers with comparable T_gs. To a first approximation, growth rates for PEO and the blends can be superposed when normalized by the degree of supercooling and T - T_g. Finally, the chapter concludes with a brief review of recent time-resolved small and wide-angle x-ray experiments conducted on PEO and the same blends.