Chemical modification of starch for high-performance bioplastics: A critical review of structure-property...

Starch is a renewable, low-cost carbohydrate polymer, yet native thermoplastic starch is brittle and humidity-sensitive. This review critically synthesizes recent advances in chemical modification that enable high-performance starch bioplastics: esterification/crosslinking, oxidation, and hydrophobization. We develop structure-property maps linking degree of substitution or crosslink density to tensile strength, elongation, and barrier properties, and we differentiate solvent-cast films from reactive extruded TPS. Emphasis is placed on humidity-aware barrier reporting and, where possible, on quantitative synthesis. Processability is treated explicitly, typical windows for reactive extrusion and deep eutectic/ionic media are summarized together with conversion metrics. End-of-life is reviewed with a focus on standards and evidence-distinguishing visual disintegration from mineralization via CO₂ evolution. The article closes with checklists for minimum reporting and design charts that connect chemistry levers to target performance. By integrating chemistry, processing, and testing standards, the review provides decision-ready guidance for translating modified starch into scalable bioplastic formulations for packaging and coating applications.