STUDY OF THE EFFECTS OF ANNEALING ON THE MECHANICAL STIFFNESS AND STRUCTURE OF ULTRA HIGH MODULUS LINEAR POLYETHYLENE

Measurements have been made of the changes in Young's modulus and structure which occur when ultra high modulus linear polyethylene is subjected to different annealing treatments. The structural measurements include the determination of the linewidths of the (200), (020) and (002) X-ray reflections, and the long period obtained from small angle X-ray scattering. It has been found that there is an excellent correlation between the Young's modulus and the longitudinal crystal thickness. This correlation holds for all annealing treatments including those which involve annealing followed by rapid quenching which leads to an initial fall in modulus followed by a significant rise, as reported by previous workers. © 1979.