Green Approaches to the Surface Modification of Cellulose: Methods and Mechanisms

Cellulose, as the most abundant renewable biopolymer on Earth, provides significant potential for sustainable material development. However, its native hydrophilicity, crystallinity, and poor compatibility with nonpolar systems limit its use in advanced applications. To overcome these challenges, a broad spectrum of organic reactions has been employed to chemically modify cellulose, enabling fine-tuning of its surface chemistry, solubility, thermal stability, and interfacial behavior. This review highlights key modification strategies, including esterification, etherification, click chemistry, and isocyanate-based urethanization, as well as oxidation methods that introduce reactive functionalities for further coupling. The discussion includes both dispersion-based (heterogeneous) and solution-based (homogeneous) reaction systems, emphasizing the influence of reaction conditions, solvent selection, and catalytic approaches. These organic transformation routes allow the integration of cellulose into a wide range of functional materials such as biodegradable plastics, hydrophobic coatings, biomedical scaffolds, flame-retardant composites, and flexible electronics, thereby positioning chemically modified cellulose as a versatile platform for next-generation sustainable technologies.