Hedrites are clusters of multilayer lamellar crystallites. A hedrite that is seen flat-on has hexagonal shape (hexagonit). A fan-like arrangement of lamellae around a central axis perpendicular to the plane of the hexagonite was observed. On the surfaces of lamellae seen flat-on, hexagonal etch pits appear referring to screw dislocations. They are responsible for branching and proliferation of lamellae. Due to the branches of lamellae, two formations develop symmetrically to the plane of the hexagonite, like a flower-cup. The lamellae are cup-shaped having two-dimensional curvatures. In ovalites developed from a rod-like precursor the majority of lamellae is seen edge-on. The top-view of lamellae standing on the edge is C-shaped, i.e. they are curved. Hedrites may reach considerable sizes presumably due to a co-ordinated co-operative growth of lamellae. There is an unequivocal correlation between the character of birefringence and the morphological structure shown by SEM of hexagonites, rods, ovalites and banded spherulites. It was shown that the banded structure of β-spherulites is produced due to a co-ordinated twisting of a bundle of the growing lamellae.
|Translated title of the contribution||Crystallization and melting of polymers, XXVII. Lamellar structure of β-polypropylene studied by scanning electron microscopy|
|Number of pages||6|
|Journal||Magyar Kemiai Folyoirat, Kemiai Kozlemenyek|
|Publication status||Published - Aug 1 1997|
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