Tough and biodegradable film from modified carboxymethyl cellulose crosslinked gelatin

Gelatin's renewable and biodegradable properties establish it as a promising alternative to fossil-based plastics. However, extensive intermolecular hydrogen bonding in gelatin restricts chain mobility, resulting in limited processing capabilities. This study utilizes aldehyde-functionalized carboxymethyl cellulose fibers as a cross-linking agent for gelatin, enhancing intermolecular interactions by substituting hydrogen bonds with dynamic covalent bonds. Through modification of the dynamic covalent network structure, the gelatin film exhibits substantially improved mechanical and thermal properties, achieving a fracture stress of 26.85 ± 1.87 MPa and fracture strain of 65.0 ± 3.5 %, enabling it to support a 1 kg weight effectively. Furthermore, the film demonstrates superior resistance to water and UV radiation, coupled with exceptional self-healing capabilities, biodegradability, and recyclability. The production process for the gelatin film remains straightforward and excludes harmful solvents. These collective characteristics establish gelatin-based plastics as a viable substitute for fossil-based plastics, offering a sustainable solution for high-performance applications.