Preparation of chitosan/gelatin composite foam with ternary solvents of dioxane/acetic acid/water and its water absorption capacity

Green superabsorbent polymer has attracted more attention in recent years. In this study, the natural-derived polymers of chitosan and gelatin composite foam with excellent water absorption capacity (WAC) were successfully prepared with ternary solvents. The optimal process parameters are: chitosan/gelatin mass ratio of 90:10 (w/w), ternary solvents of dioxane/acetic acid/water=2:0.8:77.2 (v/v/v), chitosan/gelatin total concentration of 1% (w/v), and freezing temperature of -196 degrees C. Under the optimal conditions, the prepared chitosan/gelatin composite foam reached water absorption equilibrium less than 60 min and the WAC was 651 g/g. The composite foam also had excellent WAC in a wide range of pH, temperature, and salt concentration. It demonstrates that water absorption capacity can be improved by combining chitosan with gelatin without chemical modification and optimizing the physical microstructure by the ternary solvents system and freezing temperature. The non-toxic chitosan/gelatin composite foam with super water absorbency can find potential applications especially in the fields of hygiene and biomedicine.