Open AccessMolecular mobility in bulk and in near-surface nano-layers of ultra-high-molecular-weight polyethylene
Author(s) -
V. I. Siklitsky,
A K Gladkov,
Е. М. Иванькова,
D. V. Lebedev,
L. P. Myasnikova,
V. A. Marikhin,
O. Yu. Solov’eva
Publication year - 2021
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/2103/1/012227
Subject(s) - materials science , crystallization , thermoluminescence , polyethylene , molecular dynamics , relaxation (psychology) , chemical engineering , nano , electron mobility , analytical chemistry (journal) , luminescence , composite material , chemistry , organic chemistry , optoelectronics , psychology , social psychology , computational chemistry , engineering
A comparative study of molecular dynamics in near-surface nanolayers and in a bulk of polyethylene is presented. Molecular mobility in near-surface nanolayers of polyethylene reactor powders and melt-crystallized films of various molecular weights prepared in different crystallization conditions were studied with the help of thermoluminescence technique using high frequency glow dicharge Ar plasma for surface activation. Molecular mobility in a bulk of the same samples was investigated by the method of radio thermoluminescence, in which a deeply penetrating γ-quanta from 60 Co radiation was used for activation of the bulk. A marked difference in a temperature position of the peaks on the glow curves of plasma-induced thermoluminescence and those of radiothermoluminescence correspoding to γ- and ß-transitions was found to depend on crystallisation conditions and molecular weight. Quasi-independent segmental mobility (ß-relaxation) in the near-surface nano-layers of UHMWPE reactor powder particles synthesized at low temperatures appeared to be unexpectedly unfreezed at the temperature higher than that in the bulk. It was supposed that this happend because of crystallization under the confinement conditions during low-temperature polymerization leads to formation of a specific surface structure.