Thermally Stimulated Depolarized Current (TSDC) Analysis on the Structural Change of Regenerated Cellulose Membranes Caused by the Change in Water Content
1996; Springer Nature; Volume: 28; Issue: 12 Linguagem: Inglês
10.1295/polymj.28.1077
ISSN1349-0540
AutoresTomoko Hongo, Toshinori Koizumi, Chihiro Yamane, Kunihiko Okajima,
Tópico(s)Magnetic and Electromagnetic Effects
ResumoStructural change of regenerated cellulose membranes caused by the vaporization of water was investigated with aid of thermally stimulated depolarized current (TSDC) analysis. For this purpose five kinds of regenerated cellulose membranes having different swelling anisotropy parameter Lt and plane orientation factor f‖(11̅0) were utilized. The membranes first dipped in water at 25°C for 5 min were subject to TSC measurement as a function of annealing temperature Ta from 10 to 130°C. The two broad TSC β and TSC γ relaxations were observed and the former peak was found to decrease in its depolarized current Iβ with an increase in Ta while Iy of the latter also decreases up to Ta=Tt2 then increases. It was found that these relaxations were composed of at least three and two components, respectively, by thermal window analysis reducing to ΔS*−ΔH* relation, and correspond to mechanical relaxations and β observed on tanδ−T curves. The peak temperatures (Tβ and Tγ) and their currents (Iβ and Iγ) as a function of Ta, and lnTβ−1/Ta plot revealed two sudden molecular integration region around Ta=30–50 and Ta=50–80°C, of which former relates to the sudden change in long periodicity of (11̅0) plane. The ratio of Iβ and Iγ at the above Tt2 was proved to be closely related to Lt and f‖(11̅0).
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