کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1484547 991634 2008 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Dielectric relaxation of water adsorbed on cellulose
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
Dielectric relaxation of water adsorbed on cellulose
چکیده انگلیسی

Water is an essential part of the structure of biological materials. To estimate how the physical state of water adsorbed on cellulose affects various properties, the dielectric properties of moist cellulose were investigated. Three dielectric relaxations were obtained. The relaxation with the lowest frequency was due to electrode polarization. The direct-current conduction calculated from the dielectric loss leaving out the relaxations appearing in mid and high frequencies increased rapidly from 7% or more moisture content (MC). Free water, which can dissolve electrolytes, was increased in the adsorbed water of materials with 7% or more MC. The relaxation appearing in the mid-frequency range was due to interfacial polarization in the heterogeneous structure which consists of adsorbed water with large electrical conductivity within the insulating cellulose. The relaxation appearing at higher frequencies was due to the motion of adsorbed water in cellulose. The relaxation was investigated from relationships between activation enthalpy and entropy in the relaxation. The relationships in low MC cellulose were close to those of sugar, while the relationships in high MC cellulose were close to the relationships extrapolated from bulk water.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Non-Crystalline Solids - Volume 354, Issue 27, 1 June 2008, Pages 3220–3224
نویسندگان
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