X-ray studies of surface melting in single crystals of linear polyethylene

Abstract

X-ray diffraction by annealed single crystal mats of linear polyethylene was studied as a function of temperature. The intensity of small-angle scattering changed reversibly with temperature, but the long-period remained constant. The crystal thickness along the molecular chain, which was evaluated from the line width of the wide-angle 002 reflection, began to decrease in the vicinity of 60°C. The change in the intensity of the 002 reflection also indicated the decrease in the number of crystal lattices. From these facts surface melting of the crystal was inferred.