Temperature dependence of morphology of supermolecular structures growing in the thin layer melt of fractions of poly(ethylene oxide)

Abstract

Abstract Poly(ethylene oxide) fractions with molecular weights in the range from 1.55 × 103 to 1.5 × 105 were studied. The optical microscopic observations of the morphology of supermolecular structures grown isothermally from the melt were used to determine the dependance of structural-morphological changes on temperature. Two morphological transitions were established: (1) a high temperature transition at 49 [Ptilde] 3° C from hedritic structures to positive spherulitoids and (2) a low temperature transition at 38 [Ptilde] 2° C from positive spherulitoids to negative spherulites. It is supposed that the transition from hedrites to positive spherulitoids proceeds through a transition from b-axis-oriented lamellae with tilted chains to [401] lamellae with chains perpendicular to the lamellar surface.