Ultradrawing of high molecular weight polyethylene films produced by gelation/crystallization from solution: Effect of the number of entanglements

Abstract

This paper describes the morphological properties of gel films of ultrahigh molecular weight (6×106) polyethylene by smallangle X-ray scattering (SAXS), wide angle X-ray diffraction (WAXD), and scanning electron microscopy. The gel films were prepared by crystallization from solution with critical concentration associated with the maximum drawability of the dry gelfilms. Through a series of experimental results, it turns out that the number of entanglements causes significant changes in the profile of SAXS intensity distribution and in the orientation of crystallites estimated by WAXD patterns. Furthermore, stress-strain curves were dependent upon an increase of the entanglements. Based on the above results, it may be concluded that a suitable levelof entanglements between crystal lamellae plays an important role for transmitting drawing force as intermolecular crosslinks in an ultradrawing process. © 1985 The Society of Polymer Science, Japan.