Application of Natural Deep Eutectic Solvents as Plasticizer in Natural Polymeric Films Preparation

D eep eutectic solvents (DES) are an alternative for ionic liquids (ILs). These solvents are biodegradable, non- or low-toxic compounds that obtained via simple and convenient way. They are usually prepared by complexing of a hydrogen bond acceptor (HBA) and a hydrogen bond donor (HBD), forming a deep eutectic mixture, in such a way that the melting point of the  mixture is much lower than the melting points of each component. The recent discovery of natural deep eutectic solvents (NADES) has accelerated their use as an alternative to conventional organic solvents, which are inherently toxic and highly volatile. Polysaccharides are the most abundant natural polymers and are considered as prospective starting resources for the production of green materials and replacement of non-biodegradable plastics. However, films made from pure polysaccharides are usually brittle and demonstrate poor mechanical properties, that limit their use.This has led to to the development of polysaccharide-based materials modified either chemically or by the addition of reinforcing fillers and plasticizers. To date, NADES have been used not only in the extraction, separation or purification of some specific biopolymers, but also as components of polysaccharide-based materials, e.g. plasticizers, compatibilizers or modifiers. NADESs are used as plasticizer, mainly for starch films, however it is also used for cellulose derivatives, chitosan, agar and agarose. In this paper, the potential application of NADES as green, inexpensive and sustainable plasticizers in the production of natural polymer films is reviewed.