Aqueous Modification of Chitosan with Itaconic Acid to Produce Strong Oxygen Barrier Film

Abstract

In this study, the chemical modification of chitosan using itaconic acid as a natural-based unsaturated dicarboxylic acid was investigated. In an aqueous environment, the amine group of chitosan reacts with itaconic acid to produce a chitosan derivative with pyrrolidone-4-carboxylic acid group. On the basis of the elemental analysis, 15% of the amine groups of chitosan reacted, thus creating modified chitosan with amine and carboxylic acid functionalities. Due to the presence of amine and carboxylic acid groups, the surface charge properties of the chitosan were notably altered after itaconic acid modification. In an aqueous solution, the modified chitosan exhibited zwitterionic properties, being cationic at low pH and turning anionic when the pH was increased over 6.5, whereas the original chitosan remained cationic until pH 9. Furthermore, it was demostrated that the modified chitosan was suitable for the preparation of a self-standing film with similarly high transparency but notably higher mechanical strength and oxygen barrier properties compared to a film made from the original chitosan. In addition, the thermal stability of the modified chitosan film was higher than that of the original chitosan film, and the modified chitosan exhibited flame-retardant properties.

Recent Advances in Biotechnological Itaconic Acid Production, and Application for a Sustainable Approach

“…These biopolymers are polysaccharides (i.e., starch, cellulose, chitosan, alginic acid, hyaluronic acid, pullulan, and carrageenan) [ 107 , 108 ], proteins (i.e., whey protein, and gelatin), and various other natural polymers [ 109 ]. Together with the integrated IA, these bio-based polymers influence the functional characteristics of biopolymer-based films, such as antioxidant, antimicrobial, barrier feature, mechanical strength, or thermal stability [ 110 , 111 , 112 , 113 ].…”

“…The modified chitosan film was prepared through the dissolution in an IA suspension. In comparison with films made just from chitosan, the IA adjusted film had improved characteristics, like more efficient oxygen barrier (191 (cm 3 ·μm/m 2 ·day·atm), enhanced mechanical strength (tensile strength: 53 MPa), increased thermal constancy (243 °C), and flame-retardant assets [ 113 ]. Furthermore, chitosan, IA, and hyaluronic acid, a novel hydrogel composite for Mn absorption, were produced through gamma radiation, at room temperature, and through crosslinking and free radical polymerization.…”

“… Biopolymers synthesized from IA for water treatment applicabilities ( A ). Modified chitosan with itaconic acid (adapted after [ 113 ]) ( B ). Guar gum grafted itaconic acid (adapted after [ 120 ]) ( C ).…”

Chitosan Functionalization: Covalent and Non-Covalent Interactions and Their Characterization

“…Lastly, 1,4-nucleophilic additions of CS amines to α,β-unsaturated carbonyls were recently reported in the literature for covalent conjugation purposes. These aza-Michael reactions involve acrylate derivatives such as methyl acrylate [ 87 ], itaconic acid (IA) [ 88 ], or glycidyl methacrylate [ 71 ]. Interestingly, 1,4-addition of CS amines to IA was performed in aqueous solution at 90 °C, without the need for any promoter, leading to a di-carboxylic acid intermediate that spontaneously cyclized to the corresponding pyrrolidone derivative, with an overall grafting degree of 10% ( Scheme 6 ).…”

“…Although quite rare, solid state 13 C NMR was also used for the analysis of CS derivatives when liquid state NMR was not appropriate [ 6 , 55 , 88 , 89 ]. This technique is especially useful for the characterization of CS derivatives designed to be insoluble in common aqueous and organic solvents, such as in the case of films, beads, or membranes for water treatments [ 6 , 130 ].…”