Effect of Temperature and a Non-Solvent Addition on the Specific Volume of Poly (Sodium-4-Styrene Sulfonate) in Water

The effect of temperature and a non-solvent, ethanol, addition on the specific volume of poly (sodium 4-styrene sulfonate) in water was investigated. The refractive indices of the studied solutions were measured over the 298.15–323.15 K temperature range. Then, the specific volumes of the polyelectrolyte were calculated according to the Lorentz–Lorenz and Gladstone–Dale equations. The relative deviations of the specific volumes between measured and calculated according to these equations did not exceed 2.5%. Several empirical equations were deduced to describe the variations of the refractive index increment and the specific volume versus the temperature and the mixture composition.