Effects of removing small fragment with ultrafiltration treatment and ultrasonic conditions on degradation kinetics of chitosan

Abstract

The objective of this study was to explore the effect of removing smaller degraded molecules with ultrafiltration treatment and ultrasonic conditions on the degradation kinetics of chitosan. The following results were obtained. The molecular weight of chitosan decreased faster for dilute chitosan solutions than for higher-concentration ones, and it decreased with sonolysis time. The molecular weights of chitosan solutions treated at 30 °C were lower than those treated at 0 or 50 °C. The molecular weights of chitosan solutions, which underwent concurrent removal of smaller degraded molecules during sonolysis, were lower than those without the concurrent removal of degraded molecules. The degradation rate constant remained relatively constant during sonolysis; however, it increased with decreasing solution concentration. Degradation rate constants of solutions treated at 30 °C were higher than those treated at 0 or 50 °C. Removing smaller degraded molecules during sonolysis resulted in higher rate constants than for solutions in which the smaller degraded fragments were not removed.