Montmorillonite‐Reinforced Starch Films: Recent Advances in Nanocomposite Design for Sustainable Food Packaging

ABSTRACT

The increasing demand for sustainable packaging materials has intensified interest in biodegradable alternatives to petroleum‐based plastics. Starch‐based films are renewable, compostable, and widely available, but their application in food packaging remains limited by poor mechanical strength, high water sensitivity, and insufficient barrier performance. This review discusses recent advances in montmorillonite (MMT)‐reinforced starch films, emphasizing how polymer–clay interactions, intercalation, exfoliation, and percolated network formation improve structural, thermal, mechanical, and barrier properties. Particular attention is given to the influence of processing strategies, including solution casting, melt extrusion, ultrasonication‐assisted dispersion, crosslinking, and emerging coating/printing routes, on MMT dispersion and nanocomposite morphology. Across representative formulations, MMT‐based reinforcement has been associated with tensile‐strength increases of approximately 40%–154%, Young's modulus increases above 70% in optimized hybrid systems, and water‐vapor or oxygen‐barrier reductions commonly ranging from about 25% to 60%, depending on starch source, plasticizer content, filler loading, and dispersion quality. Food‐packaging applications are critically reviewed, with case studies showing shelf‐life extension in perishable products such as strawberries, paneer, chicken, and litchi through reduced moisture loss, microbial spoilage, and oxidative degradation. Intelligent applications, including spoilage detection through pH‐induced color changes, are also discussed. Finally, the review addresses remaining challenges related to large‐scale processing, nanoparticle dispersion, food‐contact safety, compostability, aquatic degradation, and cost‐efficiency. Overall, MMT–starch nanocomposite films represent a promising platform for active and intelligent food packaging aligned with circular economy and environmental sustainability goals.