Measurements of DSC, NMR and high-frequency spectroscopy have been done on PEO-H
2O and PEO-H
2O-HQ mixed systems. DSC measurements show that water molecules contained in PEO are divided roughly into two species: freezable water and non-freezable water. By
1H-NMR measurements, PEO and H
2O protons show an absorption peak around 3.6 ppm and 4.5 ppm, respectively. All the PEO-H
2O samples containing H
2O show NMR absorption signals, suggesting the existence of movable H
2O. Samples with H
2O molar ratio over 0.5, show one absorption peak of H
2O protons, and more than two peaks of PEO. The results from DSC and NMR measurements show that the bound state of H
2O in PEO, as well as the mobility of PEO itself, varies according to the water content in PEO-H
2O samples. On the other hand, DSC measurements give the result that PEO-H
2O-HQ systems can be considered as homogeneous so long as the content of H
2O and/or HQ is not so high. Furthermore, the water molecules in the system exist as bound water. Results of high-frequency spectroscopic measurements for the PEO-H
2O and PEO-H
2O-HQ systems show good agreement with those of DSC and NMR measurements.
View full abstract