CRYSTALLIZATION OF CRYSTALLIZABLE AND AMORPHOUS POLYMER MIXTURES AND PECULIARITIES OF THEIR STRUCTURE - AN NMR-STUDY

After isothermal crystallization of the crystallizable poly(ethylene o xide)/amorphous poly(propylene oxide) mixture, partially crystalline s tructures were formed. They present a specific heterogeneous medium wi th a hard frame composed of the crystal phase. The isothermal crystall ization of the mixture and molecular self-diffusion processes in the a morphous phase of the crystallized mixture was studied by nuclear magn etic resonance relaxation and nuclear magnetic resonance (NMR) with pu lsed field gradient. The temporal dependencies of the apparent self-di ffusion coefficient were analyzed and the heterogeneity sizes were est imated, The dependence of the heterogeneity size on the crystallizatio n temperature can be qualitatively described by parameter delta, which includes the linear growth rate of the crystal and diffusion coeffici ent of the amorphous (more mobile) component. (C) 1998 Elsevier Scienc e Inc.