Chitin–clay composite gels with enhanced thermal stability prepared in a green and facile approach

Abstract

Chitin–clay composite hydrogels were successfully fabricated through a facile alkali and freeze treatment. Systematic structure–property relationships based on different compositions of the composite systems were determined. It was found that addition of clay considerably increased the thermal stability as indicated by increases in initial decomposition temperature compared to pure chitin. The increase in activation energy of degradation calculated by the Coats–Redfern method supported the thermal stabilization. For other properties, clay decrease water content, swelling ratio and porosity of gel materials. The morphology indicated they underwent a transition from clay clusters as the dispersive phase to clay flakes as the matrix. Wide angle X-ray scattering results suggested that clay-hindered crystallization of chitin. Fourier-transform infrared spectroscopy results indicated that freezing induced specific interactions while incorporation of clay-hindered deacetylation. This work provides a simple and green method to prepare chitin–clay composites gel materials.