STUDIES ON THE 2ND VIRIAL-COEFFICIENT OF SODIUM ALGINATE SOLUTION

Based on the measurement of the concentration dependence of the osmoti c pressure of sodium alginate aqueous solution in different concentrat ions of potassium nitrate, the contribution of polyion charges to the second virial coefficient was predicted. According to this analysis, a n equation A(2) = A(2, O) + A(2, D) was obtained, and a method was int roduced to determine the theta-point of polyelectrolyte solution from A(2) determined by membrane osmometry. This is important in the invest igation field of polymer solution theory and was proved to be correct if each polyelectrolyte molecule was ionized completely. The theta-sol vent of sodium alginate aqueous solution was measured to be the concen tration in 1.41 molar potassium nitrate per litre at 30 degrees C, and this experimental result indicated that Manning's polyelectrolyte sol ution theory model is fairly successful in explaining the colligative properties of polyelectrolyte solution. (C) 1997 by John Wiley & Sons, Ltd.