Lamella alignment ratio: a SAXS analysis technique for macromolecules

Polyethylenes with various morphologies were analysed, as a function of strain and radiation doses, using a novel lamella alignment ratio (LAR) technique on data obtained from small-angle X-ray scattering (SAXS) measurements at the Diamond Light Source synchrotron. The authors have used this technique previously to describe the influence of irradiation dose on crystal morphologies of orthopaedic grade polyethylenes. The aim of the current work is to highlight and explain the effectiveness of the LAR technique as an analysis tool for macromolecular crystal reorganization, crystallographic structural changes and crystal deformation during simultaneous strain measurements. Using new data for polyethylenes with varying morphology and irradiation dosage, the effectiveness of the technique is detailed. These findings are particularly useful for polymeric materials used in property critical applications and present a facile method for SAXS analysis. It is proposed that this method could potentially be used as a convenient route for the analysis of conditioning and crosslinking mechanisms on crystallographic relationships in more complex monomeric structures.