CHITIN HYDROGEL PREPARED AT VARIOUS TEMPERATURE OF WATER VAPOR–INDUCED PHASE INVERSION

"Chitin solutions were obtained by dissolving chitin extracted from crab shell waste in N,N-dimethylacetamide (DMAc) solvent, in the presence of 5, 7 and 10% lithium chloride (LiCl). Then, the concentrated chitin solution was subjected to water vapor-induced phase inversion to prepare the chitin hydrogel. The properties of the resultant chitin hydrogel having various LiCl concentrations were determined after coagulating at different temperatures of the water vapor, namely, 5, 20 and 60 °C. The viscosity of the chitin solutions decreased when the temperature increased, suggesting the formation of the hydrogel could be accelerated by applying heat. After the chitin solution was coagulated, the resultant hydrogels prepared at higher temperature of water vapor provided better properties than those of the others. When the concentration of LiCl in the hydrogel was 7%, the water content values decreased from 407 to 359%, and the tensile strength increased from 447 to 737 kPa as the temperature was adjusted from 5 to 60 °C, respectively. As for viscoelasticity, the storage modulus of the chitin hydrogels indicated that the increment in the LiCl concentration to 7% and the water-vapor temperature of 60 °C could form a tighter structure of the hydrogels. Considering the green preparation route of the chitin hydrogels and their obtained characteristics, they can be considered as promising materials for applications where such properties required, such as in the biomedical and agricultural sectors."