The global shift away from petroleum dependence has driven intensive research into polysaccharide-based materials. Chitin, the second most abundant natural polymer, offers renewability and biodegradability. However, chitin nanofiber (ChNF) films have traditionally suffered from poor water resistance and limited functionality.
The research team, led by Ji Yali from the State Key Laboratory of Advanced Fiber Materials, College of Materials Science and Engineering at Donghua University, developed a novel film by incorporating tannic acid (TA) into deacidified ChNFs. The preparation process involved partial deacetylation of chitin, ultrasonication to obtain ChNFs, reverse dialysis for deacidification, and vacuum heat treatment to promote covalent crosslinking between TA and chitin.
The results were remarkable. The CTF film achieved a dry-state tensile strength of (145.1 ± 9.3) MPa and an elastic modulus of (5.8 ± 0.8) GPa. In the wet state, CTF maintained a tensile strength of (16.0 ± 1.5) MPa—approximately three times that of the film without TA. The film also demonstrated complete UV shielding below 319 nm and strong oxygen barrier properties, with oxygen permeability three orders of magnitude lower than that of PE films.
Crucially, CTF exhibited exceptional antioxidant activity, with DPPH and ABTS free-radical scavenging rates both exceeding 95%, along with significant antibacterial activity against both S. aureus and E. coli. In a 7-day strawberry preservation test, strawberries sealed with CTF remained intact and mold-free, while those sealed with PE film or CF film (without TA) showed accelerated ripening or mold growth.
The innovation lies in the physicochemical crosslinking between TA and chitin, which consumes hydrophilic amino and hydroxyl groups, reduces water absorption, and simultaneously imparts antioxidant, antibacterial, and UV-shielding functionalities. This synergistic effect enables the CTF film to create an optimal micro-environment for fruit storage—balancing humidity, limiting oxygen, and inhibiting microbial growth.
This sustainable, high-performance film offers a promising alternative to traditional petroleum-based packaging materials, contributing to reduced plastic pollution and improved food preservation.
The work entitled “Performance Evaluation and Application Exploration of Deacidified Chitin Nanofibril Film” was published in Journal of Donghua University (English Edition) (published in Issue 02, 2026).
DOI: 10.19884/j.1672-5220.2025-01006