Heat of dilution of aqueous solutions of sodium carboxymethylcellulose and sodium polyacrylate

The heats of dilution (ΔH) of aqueous solutions of sodium carboxymethylcellulose (NaCMC) having degrees of etherification of 0.75 and 1.4, were measured. Data for NaCMC at 25°C were in good agreement with Manning's limiting law, whereas this was not the case for sodium polyacrylate (NaPAA) at 25°C. The ΔH values of NaCMC and NaPAA at 40°C were in agreement with the theory. It was found that Manning's limiting law satisfactorily described the dependence of the ΔH of polyelectrolytes on the concentration, charge density, and temperature.