Crystallite size distribution and lattice distortions in polyethylene from analyses of Debye-Scherrer line profiles

Publisher Website
Google Scholar
Abstract
Distributions of crystallite sizes and lattice distortions in the direction normal to (110) of the polyethylene crystal are derived from 110 Debye‐Scherrer profiles, by means of a Fourier technique developed by one of the present authors. Samples investigated are linear polyethylene powder, single‐crystal mats grown at 85 °C and 70 °C, and branched polyethylene powder with a different methyl‐group concentration. It is found that in the crystallite size distribution each of the polyethylenes examined has a common peak at about 100, 250, 350, and 450 Å. The presence of branches with lower methyl concentration does not seriously affect the distribution, but at the highest concentration of branches (29 CH3/1000 CH2) peaks at 350 and 450 Å disappear. Lattice distortions in the crystallites of polyethylene cannot be always explained by paracrystalline or strained‐lattice‐type strain alone, but may be generally expressed by a superposition of them.