Morphology of Polymer Single Crystals

Abstract
Evidence is presented indicating that polyethylene crystals grow in the form of hollow pyramids as well as lamellar crystals. Modes of packing the folded molecules consistent with the nonplanar structure are proposed. Observed electron diffraction patterns and dark‐field micrographs are related to the pyramidal morphology. Various sources are described for the screw dislocations which result in spiral growths on crystals of polyethylene and polyoxymethylene.