SWELLING OF MEMBRANES FROM THE POLYELECTROLYTE COMPLEX BETWEEN CHITOSAN AND CARBOXYMETHYL CELLULOSE

The swelling of membranes of polyelectrolyte complexes formed from chi tosan and carboxymethyl cellulose is reported. These membranes adsorb water until a maximum swelling is achieved after which they slowly shr ink to an equilibrium value. The maximum swelling value and the time a t which it is attained increases as the pH of formation of the complex increases from 4.0 to 5.8. Shrinkage observed at longer times is the result of the segmental mobility of the polyelectrolyte chains in the swollen state which allows the completion of the interpolyelectrolyte reaction. The water uptake up to maximum swelling obeys second order k inetics.