Molecular mobility in near-surface nano-layers of ultra-high molecular weight polyethylene as revealed by thermoluminescence activated by low temperature Ar plasma

Abstract

Aiming at better understanding the properties of the near-surface nano-layers of UHMWPE reactorpowders (RP) used for manufacturing high-performance fibers by solvent-free processing, acomparative study of the molecular mobility in the nano-layers of two different UHMWPE RP andits change after compaction and sintering is carried out with the help of thermoluminescence method.The dependence of the intensity of light quanta emitted by heated samples (previously evacuated,cooled to 77 K, and activated by low-temperature argon plasma) on the heating temperature (glowcurves) is analyzed. The glow curves were recorded using a unique Nanoluminograph device, whichexists in a single copy at Ioffe Institute. It was found that all the glow curves observed had thecomplicate profiles, which evidenced the overlapping of a number of relaxation processes. The Fityksoftware was used for deconvolution the experimental curves into elementary peaks. The length ofthe so-called kinetic unit of motion (the mobility of which is defreezing in the temperature intervalof each elementary peak) was calculated. The influence of the behavior of the near-surface RPnano-layer during compaction/sintering on the achieved strength of the oriented final film threads isdemonstrated.