Chitosan as Reinforcement for Biopolymers - A Mini Review Dabertrand M, Audonnet F and de Baynast H* Université Clermont Auvergne, Clermont Auvergne INP, CNRS, Institut Pascal, F-63000 Clermont-Ferrand, France Introduction Packaging is nowadays one of the main polluting fields, particularly because of plastic packaging [1,2]. Plastic world production was 367 million tons in 2020 [3]. It generates a massive amount of waste, which is not enough valorized [4]. As the field grows, it is urgent to find new packaging solutions that preserve food from spoiling and have a lower environmental impact. For those reasons, biopolymers seem promising to replace oil-based polymers currently used [5,6]. More precisely, biopolymers such as Polylactic Acid (PLA) [7,8], starch [9,10], Polybutylene Succinate (PBS) [11-13], Poly (Butylene Succinate-Co-Butylene Adipate) (PBSA) [12,13], and Polybutylene Adipate Terephthalate (PBAT) [14,15] are widely studied [16,17]. Those polymers can be transformed by thermomechanical processes (injection, extrusion, thermoforming), which is an advantage for industrial production. However, biopolymers also have drawbacks. Mechanical, barrier and optical properties can be weak for some applications. Design composites can be an interesting way to improve polymer’s properties. To produce those structures, reinforcements are dispersed in polymers matrix. Cellulose, silica, clay, and alumina are the main studied reinforcements [18]. Nonetheless, chitosan has proved that it could be an interesting candidate due to its antimicrobial properties [19-23]. This property could increase the shelf life of food products and limit spoilage. Thus, this review aims to present the recent advances in biopolymers reinforcement with chitosan. Chitosan Chitosan is a polysaccharide derived from chitin by deacetylation (Figure 1); [24,25]. Chitin is extracted from shellfish skeletons and exoskeletons, mainly from crustacean shells. Seafood industry generates 80.000 tons of waste per year [26]. Consequently, it could be interesting to recover this material. Chitosan is biodegradable, biocompatible, non-toxic, antimicrobial. It is also chemically modifiable, which allows to adapt the properties [21,23]. It is insoluble in water but soluble in acidic conditions. Chitosan is usually defined by its molecular weight and its Deacetylation Degree (DD). Chitosan cannot be transformed by common plastics Crimson Publishers Wings to the Research Mini Review *Corresponding author: H de Baynast, Université Clermont Auvergne, Clermont Auvergne INP, CNRS, Institut Pascal, F-63000 Clermont-Ferrand, France Submission: February 15, 2022 Published: March 09, 2022 Volume 3 - Issue 2 How to cite this article: Dabertrand M, Audonnet F, de Baynast H*. Chitosan as Reinforcement for Biopolymers - A Mini Review. Polymer Sci peer Rev J. 3(2). PSPRJ. 000557. 2022. DOI: 10.31031/PSPRJ.2022.03.000557 Copyright@ H de Baynast, This article is distributed under the terms of the Creative Commons Attribution 4.0 International License, which permits unrestricted use and redistribution provided that the original author and source are credited. 1 Polymer Science: Peer Review Journal ISSN: 2770-6613 Abstract It is nowadays urgent to find new packaging solutions that have a lower impact on the environment. Biopolymers (PLA, starch, PBAT) seem interesting to the design of the new packaging generation. These polymers have some drawbacks such as mechanical and barrier properties. Also, it could be interesting to add antimicrobial properties to packaging to increase the shelf life of food products. For those reasons, chitosan seems to be an interesting component to add to a biopolymer matrix. Chitosan is a polysaccharide derived from crustacean shells. Chitosan can be directly added to the matrix via thermomechanical processes, or it can be turned into thermoplastic chitosan with the combined effect of an acid solution, a plasticizer, heat, and shear. The chitosan intramolecular bonds are thus reduced. The second method seems to limit the agglomeration of chitosan in the polymer matrix and increase interfacial adhesion. The composite properties depend on the acid and plasticizer type and rate. Keywords: Antimicrobial properties; Biopolymer; Chitosan; Composite; Plasticised chitosane