X-Ray Line Broadening in Polyethylene Filaments

Abstract

The precise methods of obtaining X-ray line profile and broadening in crystalline high polymer using X-ray diffractometer are discussed in detail, and the causes of X-ray line broadening in highly oriented linear polyethylene ‘Marlex 50’ are investigated. It is found that the main causes are crystallite size effect and lattice-distortion, and the strain distribution function is approximated by Cauchy-form 1⁄(1+k²x²). Therefore, the separation of two effects can be made by means of Hall’s equation. Using 110 and 220 reflections on the equator, recrystallization of crystallite by annealing, break-up of crystallite with elongation and change in lattice-distortion are observed.
The obtained values of strain (1∼2%) are larger by one order of magnitude than those of cold-worked metals, and not changed so greatly by annealing and deformation, whereas crystallite size varies widely (100Å∼larger than 700Å).