Preparation and Swelling Properties of Chitosan Hydrogel Beads

Chitosan gel beads were prepared using sodium tripolyphosphate (TPP) and sodium hexametaphosphate (SHMP) composite as crosslinking agents. The influence of mass ratio of crosslinking agents, pH value and ionic strength on swelling properties of chitosan gel beads are discussed. According to the results, composite crosslinking agent can decrease the swelling degree by 62.4% and 41.3% in comparison with TPP or SHMP alone, respectively, and increase the ioniccrosslinking efficiency. The most compact chitosan beads can be obtained when m(TPP)∶m(SHMP)=3∶5 and pH=5. The swelling degree can reach up to 357% when cured in pH=1.2 buffer solution. The beads have good ionic strength and pH sensitivity and high swelling degree in acidic media.