SELF-DIFFUSION OF POLY(ETHYLENE OXIDE) FRACTIONS AND ITS INFLUENCE ON THE CRYSTALLINE TEXTURE

Two somewhat separate issues have been dealt with: the diffusion coefficients of various poly(ethylene oxide) (PEO) fractions at different temperatures; and morphological observations of spherulitic textures of a PEO mixture containing low- and high-molecular mass components at different supercooling and cooling rates. We found that simultaneous knowledge of diffusion coefficient of PEO fractions and crystal growth rate of the mixture leads to a better description of the crystal growth. As observed, the spherulitic texture of the PEO mixture comprises three texture levels: the spherulite as a whole; the crystal-growth unit comprised of different number of lamellae in a stack; and the individual lamellar crystal. Under certain crystallization conditions, the thickness of the lamellar stack is on the same order of magnitude as the parameter delta proposed by Keith and Padden.