Covalent Surface Modification of Polyester Fabric with Carvacrol and Eugenol

Abstract Synthetic fibers such as polyester (PES) are highly valued for their strength and low cost, yet their inherent hydrophobicity and poor dyeability remain significant challenges. To address these limitations sustainably, this study presents a novel surface modification of PES that combines mild lipase-catalyzed hydrolysis to generate reactive surface carboxyl groups, followed by direct esterification with the natural phenolic compounds carvacrol and eugenol. The efficacy of this functionalization was evaluated using FTIR, UV–vis, contact angle, SEM, and thermal analysis. Optimization revealed that a 40 wt % oil concentration provided the optimal balance, achieving effective surface incorporation of 8.3 mmol g–1 of fabric for carvacrol and 6.1 mmol g–1 for eugenol. FTIR, along with 5-cycle wash-fastness tests, indicated the durable formation of covalent ester bonds. The resulting modified fabrics exhibited excellent hydrophilicity (contact angle reduced from 116.17° to 0° with immediate absorption) and significantly enhanced dye diffusion and color fastness matching untreated standards. Additionally, incorporating these terpenes imparted high-value properties, notably reducing flame propagation (remaining length increasing from 2.7 cm to 4.1–4.3 cm) and inhibiting Candida albicans proliferation by 48–90%. These findings highlight a promising, eco-friendly pathway for the durable, covalent functionalization of polyester textiles.