"PREPARATION AND CHARACTERIZATION OF CHITIN HYDROGEL COMPOSITED WITH HALLOYSITE CLAY SOLUTION VIA PHASE INVERSION "

Abstract

In this study, halloysite clay (HC), a reinforcing nanofiller, was mixed with 1 and 1.5% chitin solutions to prepare chitin–halloysite clay composite hydrogel by phase inversion under water vapor atmosphere at 25 °C. Chitin, extracted chemically from crab shell, was dissolved in N,N-dimethyl acetamide in the presence of 5% lithium chloride (DMAc/5% LiCl), and then different amounts of HC solution (0, 3, 5 and 7%) were added to evaluate the effect of HC on the fundamental properties of the obtained composite hydrogels. After the green route of preparation, the diameter and thickness of the hydrogel samples seemed to remain the same, while varying the concentrations of chitin and inorganic filler solution. As a result, in the case of the 1% chitin hydrogel, the tensile strength of the composite films increased from 335.9 to 489.8 kPa, while the elongation was around 61.3 and 86.0% with the addition of 0 and 7% HC solution. With the increase in the chitin content to 1.5%, the mechanical strength of the resultant composite hydrogels was enhanced. Moreover, the reduction in the equilibrium water content confirmed the formation of a composite hydrogel incorporating a well dispersed nanofiller, with good interfacial interaction between the nanofiller and the biopolymer matrix.