Tunable hydrophobicity and biodegradability of acetylated lignin/polyester fibrous mat for water/oil separation

Abstract

The development of eco-friendly and biodegradable biopolymer composites has become increasingly important. In this study, acetylated lignin (ACL) was synthesized, and its potential as an effective additive for biodegradable polymers was investigated. ACL was synthesized through a one-step acetylation process in which hydroxyl groups of lignin were substituted with acetyl groups. ACL exhibited enhanced molecular weight and thermal stability, along with improved solubility in organic solvents compared to unmodified kraft lignin (KL). Hydrophobic ACL was uniformly dispersed in a mixture of a polycaprolactone (PCL) polymer and organic solvent, leading to the successful fabrication of a fibrous mat using electrospinning. The ACL/PCL fibrous mat demonstrated enhanced mechanical strength and hydrophobicity, notably indicating a substantially high-water contact angle of 143.3 ± 1.4°. Subsequently, it was utilized as a water/oil separator, showing a separation efficiency exceeding 90% for oil within a short time, effectively addressing water/oil emulsions. Biodegradability results demonstrated enhanced hydrolysis degradation efficiency with the incorporation of ACL into PCL fibers. Consequently, this study proposes a feasible approach to enhance the efficacy of ACL as a biodegradable polymer additive, while presenting promising opportunities for membrane applications targeting water/oil separation.