Lamellar and interlamellar structure in melt-crystallized polyethylene

Abstract

The effects of small (<20%) strain on the microstructure of Marlex 6009 polyethylene was investigatedin situ by absolute small and wide-angle X-ray diffraction. The methods of analysis given in previous papers by Kavesh and Schultz were utilized. The degree of crystallinity decreased monotonically with strain. The “amorphous” density increased with strain to some 8 to 12% strain, after which the density levelled off at a value of about 0.901. The lamellar thickness was found to decrease slightly with strain while the intervening layer thickness increased. Finally, the plane of the carbon backbone rotated toward thea-c crystallographic plane as the strain increased. The microstructural effects are interpreted in the light of molecular rearrangements in both crystalline and “amorphous” zones.