Enhancement of mechanical strength and barrier performance of carboxymethyl cellulose films using bamboo-derived amphiphilic cellulose nanofibrils

In response to the increasing demand for biodegradable and functional materials for fruit packaging, this study presents a novel edible film composed of carboxymethyl cellulose (CMC) reinforced with bamboo-derived amphiphilic cellulose nanofibrils (BA-CNF). CMC films are known for their optical transparency and complete water solubility, rendering them especially appealing for waste-free packaging applications where the film can be rinsed off and removed during fruit washing (named as wash-off removability). However, their practical use is limited by poor mechanical strength and insufficient barrier properties. To address these drawbacks while retaining their wash-off removability, BA-CNF (0–20 wt%) was incorporated into the CMC matrix. The resulting CMC/BA-CNF composite films were thoroughly assessed in terms of their optical characteristics, mechanical performance, and barrier properties against light, water, water vapor, and oxygen. The findings indicated that, at an optimal BA-CNF content of 15 wt% (based on the total solid content), the composite film showed significantly enhanced tensile strength, light-blocking ability, and water resistance, diminished gas and moisture permeability, while displaying acceptable transparency and maintaining the wash-off removability under manual rinsing. To the best of our knowledge, this is the first study to integrate amphiphilic cellulose nanofibrils into CMC-based films, offering a promising and sustainable alternative to conventional plastic packaging for fruit applications in the near future.