Swelling behavior of chitosan/pectin polyelectrolyte complex membranes.: Effect of thermal cross-linking

Membranes of the polyelectrolyte complex between chitosan and pectin were prepared by precipitating the complex from a mixture of both polysaccharides. It was shown that the swelling kinetics of these membranes follows a Fickean behavior. The membranes were heated at 120 degrees C in order to convert the -NH3+-OOC- salt bonds into amide bonds. The thermally treated membranes were stable in strongly acid and basic media. The extent of amide bond formation was followed by FTIR spectroscopy. It was found that as the reaction time increased, both the absorbance ratio A(1744)/A(1082) and the maximum swelling of the membrane decreased. The surface morphology of the membranes did not vary appreciably with the thermal treatment.