Eco-Friendly Thermoplastic Starch Nanocomposite Films Reinforced with Microfibrillated Cellulose (MFC) from Fraxinus uhdei (Wenz.) Lingelsh

Abstract

Featured Application: Starch films reinforced with microfibrillated cellulose (MFC), extracted from Fraxinus uhdei (Wenz.) Lingelsh, represent a promising alternative for the development of sustainable packaging in the food industry. The incorporation of MFC significantly improved the mechanical properties of the starch films, increasing their strength and flexibility, while reducing water and oxygen permeability, critical factors for extending the shelf life of food. Furthermore, as it is a biodegradable material from a renewable source, its use contributes to reducing the environmental impact associated with conventional plastic. These films can be used in the packaging of fruit, fresh vegetables, and bakery products or as edible coatings, offering a combination of functionality, safety, and sustainability. In this work, microfibrillated cellulose (MFC) from ash branch wood was used as reinforcement in a thermoplastic starch matrix to develop environmentally friendly materials. Pulp fibers and MFCs were characterized by SEM, TEM, and FTIR. Corn starch biofilms were prepared via casting, formulating eight biofilms with 5 and 10 wt% of MFC. Also, extracts of Muicle and Hibiscus were added to incorporate antibacterial properties. The biofilms were evaluated for mechanical, thermal, and antibacterial properties. Also, properties such as color, opacity, morphology, electrical conductivity, contact angle, and solubility, among others, were evaluated. The reinforced biofilms were homogeneous, dimensionally stable, and transparent with slight color changes. MFC incorporation enhanced hydrogen bonding, which increased the ultimate tensile strength from 11.2 MPa to approximately 19–21 MPa and the Young’s modulus from 809 MPa to 1034–1192 MPa. The presence of MFC also reduced solubility from 48.7% to 38.7–39.8% and decreased water vapor permeability by about 20–23% in biofilms with 10 wt% MFC. Gas barrier properties and the glass transition temperature depended on extract type and fiber content, indicating greater rigidity. The use of ash-based MFC encourages the implementation of circular economy strategies and the development of sustainable biocomposites.