Measurements of specific heat at temperatures within the range –70°C to 120°C were obtained for the PET-water system at four different water concentrations. Water-fusion peaks for sorbed water were found in the range –15°C to 0°C. The amount of sorbed water at saturation at 0°C was 1.26 g/100 g PET, and the amount of sorbed water freezable on cooling to –70°C was 0.64 g/100 g. Integral and incremental heats of fusion of sorbed water were determined. The incremental heat, i.e., the heat necessary to melt 1 g of sorbed, freezable water, did not vary with water concentration and had the value 79 cal/g, not significantly different from bulk water. The state of the sorbed water is discussed. The specific heat data for PET is compared with previous results.
The behavior of freezable water in DMPE-water system as compared by DSC and 2H-NMR
