Specific Gravity and Dielectric Constant of Propylene Glycol-Water Mixtures, Polyethylene Glycol 400-Water Mixtures, and Glycerol-Water Mixtures

Abstract

Specific gravity and dielectric constant of polyethylene glycol and allied substances were measured. The specific gravity of a mixture of polyethylene glycol and water, and of glycerol and water increases with increasing concentration (Fig. 2), and the maximum value of specific gravity of polyethylene glycol-water system was at 60-70% concentration (Fig. 1). It is therefore assumed that the mixture of polyethylene glycol and water is in strongest association in this concentration range.
Measurement of dielectric constant was made by the phase compensation method, using the cell shown in Fig. 4. By plotting the dielectric constant against concentration, the curve shown in Fig. 3. was obtained. The dielectric constant-concentration curve was almost straight for the polyethylene glycol 400-water and of glycerol-water mixtures, indicating that association is unlikely in these cases. A specific curve was seen in polyethylene glycol-water mixture in the range of 50-90% concentration. From this fact, polyethylene glycol-water mixture is in association at 50-90% concentration and it becomes the maximum at around 60%.