高周波分光法によるPEG-H2O 混合系中の束縛水の定量分析

概要

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Application of High Frequency Spectroscopy (HFS) to the quantitative analysis of bound water in a PEG-H2O system is presented. HFS measurements were madeduring the melting process from a frozen state at -150 ℃ . Two obvious changes in resonance frequency f have been observed, one around -30℃, and the other between -20℃ and 0 ℃. These were assigned to the melting of bound and free water, respectively. From the amount of frequency change (Δf), the changes of permittivity (Δε) for the melting processes were estimated. In region XW < 0.7, the increase of Δε arising from the increase of water content was relatively small, showing that water molecules are strongly bound to the polymer chain of PEG. On the other hand, at XW > 0.7, the increase of Δε is large, showing the existence of free water molecules. These results were found to be in good agreement with those by DSC measurements.
2010-06-30