The Impact of Nickel–Zinc Ferrite Nanoparticles on the Mechanical and Barrier Properties of Green-Synthesized Chitosan Films Produced Using Natural Juices

A trend has been established concerning the research and development of various green and biodegradable plastics for multi-purpose applications, aiming to replace petroleum-based plastics. Herein, we report the synthesis of chitosan (CH) films using lemon juice; these were reinforced with NiZnFe₂O₄ nanoparticles (NiZnFe₂O₄ NPs) to obtain improved mechanical and barrier properties, facilitating their future application as sustainable, corrosion-resistant coatings for medical instruments. The synthesized NiZnFe₂O₄ NPs had a crystallite size of ~29 nm. Reinforcement with the nanoparticles in bio-sourced chitosan films was conducted at two concentrations: 1% and 2%. The mechanical strength of the CH film was found to be 1.52 MPa, while the 2% NiZnFe₂O₄ NP-containing films showed stress-bearing potential of 1.04 MPa with a larger strain value, confirming the elastic nature of the films. Furthermore, the % elongation was directly proportional to the NP concentration, with the highest value of 36.833% obtained for the 2% NP-containing films. The CH films presented improved barrier properties with the introduction of the NiZnFe₂O₄ NPs, making them promising candidates for coatings in medical instruments; this could protect such instruments from corrosion under controlled conditions. This approach not only broadens the application range of biopolymeric films but also aligns with global sustainability goals, serving to reduce the reliance on non-renewable corrosion-resistant coatings.