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Mechanical relaxation process at 208 K for highly irradiated polytetrafluoroethylene
Author(s) -
Takenaga Mitsuru
Publication year - 1987
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1987.070330818
Subject(s) - polytetrafluoroethylene , relaxation (psychology) , activation energy , glass transition , irradiation , materials science , atmospheric temperature range , polymerization , polymer chemistry , thermal , thermodynamics , composite material , nuclear magnetic resonance , chemistry , polymer , physics , psychology , social psychology , nuclear physics
The internal friction of highly irradiated samples of polytetrafluoroethylene(PTEF) was measured over the temperature range below the room temperature transition; the results indicated the appearance at 208 K of a mechanical relaxation between the γ and the β processes. The relaxation at 208 K was sensitive to effects of thermal treatments; when the relaxation weakened in intensity, the α and the β processes were emphasized. The apparent activation energy estimated was consistent with that of the relaxation which had appeared at the same temperature for as‐polymerized PTFE. The 208 K relaxation seems to be attributed to local mode motion in the intermediate phase, in which molecules arranged in parallel but with random chain separation.