1979 Volume 36 Issue 9 Pages 581-587
Highly oriented-extended-chain crystals of polyethylene (OE) were obtained by crystallization from the anisotropic melt under high pressure more than 3kbar. The anisotropic melt was thought to exist only for a short time when the drawn polyethylene was melted. The formation of OE depended strongly upon the melting time during which the transformation from anisotropic to isotropic melt took place.
Electron micrograph of the film (OE) showed a lamellar structure packed zigzag closely each other, whose average thickness was about 4, 000Å. The DSC thermogram gave a single endothermic peak at 143°C, and the degree of crystallinity was 92%. High tensile modulus and very high thermal stability were observed. Furthermore, the remarkable transparency like glass was appeared in this large OE.
From these facts, crystal orientation, voids, and flatness of surface are more important than the crystal size in the appearance of transparency.
