Kaolinite-based nanocomposites for enhancing starch and other biodegradable polymer applications in food packaging.

With the increased emphasis on sustainable food packaging solutions, naturally derived nano-fillers have emerged as highly promising reinforcements in polymer composites. Among these, Kaolinite, a phyllosilicate clay mineral with a distinctive 1:1 layered structure, is composed of alternating silica tetrahedral and alumina octahedral sheets linked by hydrogen bonding. This arrangement endows kaolinite with a high surface area and strong interlayer interactions, which enhance its compatibility with various polymer matrices, including polylactic acid (PLA), starch, etc. These properties have made kaolinite an attractive filler in biodegradable polymer composites, supporting the development of food packaging materials with reduced environmental impacts. Incorporation of kaolinite at optimal loadings (commonly 3-10 wt%) into polymer composites has been shown to enhance tensile strength, improve Young's modulus, and reduce water vapor permeability, thus substantially improving mechanical integrity and barrier performance essential for food packaging applications. This review comprehensively summarizes recent advances in the utilization of kaolinite as a natural nanofiller in polymer-based food packaging materials, emphasizing its influence on mechanical properties, flexibility, barrier functions, and environmental impact. Furthermore, this review carefully examines the safety of kaolinite for use in food packaging, including how it meets health regulations and legal requirements. It also discusses the practical challenges and opportunities involved in scaling up its use for commercial production.