Dielectric relaxation of adsorbed water in microcrystalline cellulose

Abstract

Measurements have been made to determine the dielectric properties of hydrated microcrystalline cellulose (MCC) in a frequency range from 200 MHz to 18 GHz. A broad dispersion region has been observed, characterised by a Cole-Davidson relaxation. The activation enthalpy of the characteristic relaxation time has been determined from the temperature dependence of the dispersion and corresponds roughly to two hydrogen bonds. The dispersion is identified as being due to the absorbed water and is shown to be moisture content dependent.