Sustainable biomaterials based on cellulose, chitin and chitosan composites - A review

In this review we describe recent advances of biocomposites consisting of cellulose, chitin, and chitosan. These polysaccharides are very important because they are abundant and renewable resources. As such, they significantly contribute to the development of sustainable processing of bioactive and biodegradable materials since there is an increased concern about the sustainability of synthetic polymers, leading to increased presence of microplastics in the environment. First, we briefly describe the molecular structures of cellulose, chitin, and chitosan. Our objective is to show that their related structural features lead to biopolymer dissolution in common solvents such as ionic liquids. We also address the dissolution mechanisms, biopolymer-solvent interactions, and solvent properties required to dissolve these biopolymers. Mutual solvents for of cellulose, chitin, and chitosan allow composite preparation via solution mixing which is advantageous with regard to processing complexity and costs. Thus, we present preparation, properties and application of cellulose/chitin/chitosan biocomposites in various physical forms, such as (nano)fibers, films, membranes, and hydrogels.