Chitosan Derivatives: Introducing New Functionalities with a Controlled Molecular Architecture for Innovative Materials

Abstract

The functionalization of polymeric substances is of great interest for the development of innovative materials for advanced applications. For many decades, the functionalization of chitosan has been a convenient way to improve its properties with the aim of preparing new materials with specialized characteristics. In the present review, we summarize the latest methods for the modification and derivatization of chitin and chitosan under experimental conditions, which allow a control over the macromolecular architecture. This is because an understanding of the interdependence between chemical structure and properties is an important condition for proposing innovative materials. New advances in methods and strategies of functionalization such as the click chemistry approach, grafting onto copolymerization, coupling with cyclodextrins, and reactions in ionic liquids are discussed.

Valorization of Waste: Sustainable Organocatalysts from Renewable Resources

“…It is ah ighly hydrophilic polymer due to the presence of many hydroxyl and amino groups.I na ddition to reactions common to cellulosic hydroxyl groups, chitosan reacts readily with carbonyl compounds, giving access to ester and amide derivatives, as well as Schiff bases with aldehydes, and can be readily converted into quaternary ammonium compounds. [26] Many of these reactions can be carried out under homo-orh eterogeneous conditions on the powder.…”

On the Development of Chitosan-Graft-Poly(n-Isopropylacrylamide) by Raft Polymerization Technique

“…1,2 The diversity of properties of the smart polymers with linear structures, including responsive behavior of the functional side groups to pH, temperature, ionic strength, electric or magnetic fields, and light, reversible crosslinking via non-covalent bonds that can break and reform under certain external conditions, highlight the importance of of chemical modifications. 3 As known, chitosan, with its structural specificity of having a linear β-1,4 linked glucosamine backbone, has become of interest for producing smart bio-polymers. [2][3][4][5] Its hydroxyl groups and one primary amino group in the repeating glycosidic residue act as reactive sites for a wide range of side-group attachments, including RAFT polymerization.…”

“…3 As known, chitosan, with its structural specificity of having a linear β-1,4 linked glucosamine backbone, has become of interest for producing smart bio-polymers. [2][3][4][5] Its hydroxyl groups and one primary amino group in the repeating glycosidic residue act as reactive sites for a wide range of side-group attachments, including RAFT polymerization.…”

“…RAFT polymerization of chitosan with various monomers has been reviewed recently. 2,3 Argüelles-Monal 3 reported various grafting techniques for chitosan, "grafting from" and "grafting onto" being the most relevant ones due to the fact that the polysaccharide's molecule is already established as main chain. Cheaburu-Yilmaz et al 2 explored the possibilities to "graft from" various monomers on chitosan at the hydroxyl group from C6 of the polysaccharide chain's unit.…”

“…2 The success of the RAFT polymerization was directly dependent on the selection of the chain transfer agent (CTA) suitable for the monomer type and reaction conditions. [2][3][4][5][6] An inadequate selection of the RAFT agent may lead to loss of control of the reaction, prolonged retardation and induction periods or inhibition of polymerization. The Z and R groups of the RAFT agents represent the key factors of selection, since they influence the initiation and compatibility of the generated radicals with the specific monomer used for the polymerization.…”