Vegetable Oil–Mediated Transesterification as a Green Route to Tune Ethyl Cellulose Properties

The inherent hydrophilicity of biopolymers presents significant limitations to their implementation, particularly in coating and packaging applications. Concerns regarding the toxicity, cost, and environmental impact of conventional chemical strategies for hydrophobization have prompted researchers to pursue more sustainable and eco-friendlier approaches. This study centers on a solvent-free, green, transesterification reaction (TER) to chemically graft fatty acid ethyl esters derived from diverse vegetable oils onto ethyl cellulose (EC), yielding enhancements in hydrophobicity, flexibility, and barrier performance without synthetic reagents. Successful TER of EC was verified through Fourier transform infrared spectroscopy. Among the tested oils, sunflower oil exhibited the highest TER efficiency (> 25%), attributable to high polyunsaturated fatty acid content. Atomic force microscopy confirmed a homogeneous surface morphology for TER-modified EC, while mechanical analysis revealed a threefold enhancement in elongation at break compared to unmodified EC. Moreover, oxygen and water vapor transmission rates were reduced by ~50%, signifying improved barrier properties. TER enhanced optical transparency (~82%) and surface hydrophobicity (~97°) for EC, as well as displayed better performance as a coating on substrates like wood. Integrating renewable feedstock into the TER protocol provides a potent pathway for sustainable chemical modification of EC while minimizing environmental impact by adhering to green chemistry principles.