Synthesis and structural properties of Chitin/clay bio-nanocomposites

Chitin, which is composed of 2-acetamido-2-deoxy-D-glucopyranose (N-acetyl-D-glucosamine) units linked by α-(1,4) linkage, makes up the cell walls of fungi, the exoskeletons of arthropods, such as crustaceans (e.g., crabs, lobsters and shrimps) and insects, the radulae of mollusks, and the beaks of cephalopods, including squid and octopuses. Both chitin and clay are sustainable materials, as they are low cost, biodegradable and readily available. That is why, in this study, sodium montmorillonite (CNa) nanoclay and 1-140 (C15A) organo-nanoclay were used as nanofiller support in the preparation of chitin/clay bio-nanocomposites. Trichloroacetic acid was used to dissolve the chitin and to disperse the clay in the chitin solution. Chitin/CNa and chitin/C15A bio-nanocomposites were synthesized by the solution-induced intercalation method. The effect of the nanofiller on the bio-nanocomposite was investigated by varying the loading rates as follows: 1, 3 and 5% by weight. The composites were characterized by FT-IR, XRD and SEM methods. The XRD patterns and SEM images showed that the clay dispersion in the chitin biopolymer matrix presented an exfoliated structure. It was noted that neither the nanoclay nor the organo-nanoclay used in the synthesis of the bio-composites affected the formation of the exfoliated structure. This result can be attributed to the use of a low amount of clay. These newly synthesized bio-composites, which are environmentally friendly and sustainable, can find application in many different areas in the future. © 2021, Publishing House of the Romanian Academy. All rights reserved.