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The radiation effect on thermal conductivity of high strength ultra‐high‐molecular‐weight polyethylene fiber by γ‐rays
Author(s) -
Yamanaka Atsuhiko,
Izumi Yoshinobu,
Kitagawa Tooru,
Terada Takaya,
Sugihara Hideki,
Hirahata Hiroshi,
Ema Kimiko,
Fujishiro Hiroyuki,
Nishijima Shigehiro
Publication year - 2006
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.24227
Subject(s) - differential scanning calorimetry , materials science , thermal conductivity , polyethylene , amorphous solid , fiber , composite material , thermal treatment , chemistry , thermodynamics , crystallography , physics
To understand the contribution to thermal conductivity by the length of the molecular chains in high strength ultra‐high‐molecular‐weight polyethylene (UHMW‐PE) fiber, the thermal conductivity in the range of low temperature was investigated for high‐strength UHMW‐PE fiber (Toyobo, Dyneema®; hereinafter abbreviated to DF) irradiated by γ‐rays (γ‐rays treatment) that induce the molecular chains scission. The molecular weight of DF decreased by γ‐rays treatment. X‐ray diffraction behavior did not change by γ‐rays treatment. The melting behavior observed by differential scanning calorimetry showed the main chain scission of DF by γ‐rays treatment. Heat capacity decreased slightly by γ‐rays treatment. Thermal conductivities of DF with and without γ‐rays treatment decreased by decreasing temperature. Thermal conductivity of DF decreased very much by γ‐rays treatment. The decrease of thermal conductivity was explained by molecular chain scission in DF by γ‐rays treatment and it suggested the possibility of the reduction of mean free path of phonon. The decreasing rates of thermal conductivity by γ‐rays treatment were smaller than those of molecular weight. Those differences were explained by the difference of probability of chain scission between the amorphous and crystal region. Those results suggested the contribution of the length of extended molecular chains because of high molecular weight on the thermal conductivity of DF. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2619–2626, 2006