Tailoring polysaccharide tanning agents with a broad molecular weight distribution from corncob biomass: A dual solution for sustainable leather processing and waste valorization.

The shift toward chromium-free eco-leather manufacturing has spurred interest in biomass-based tanning agents. However, their suboptimal molecular size and poor solubility hinder effective leather penetration. In this study, biomass-derived tanning agents were developed from corncob hemicellulosic polysaccharides (CPs) with tailored molecular weights, isolated via alkali extraction and acid-alcohol precipitation, followed by partial epoxidation. This process yielded three epoxidized agents (CPs-GTE), which were characterized in terms of molecular structure, chemical composition, surface morphology, and particle size distribution. Leather tanned with CPs-GTE exhibited enhanced thermal stability (shrinkage temperature > 80 °C), mechanical strength (tensile strength ≥24.302 ± 2.79 MPa, tear strength ≥36.488 ± 1.08 N/mm), and thickness (≥ 50.226 %). Among the tested samples, CP3-GTE demonstrated the most superior overall performance, highlighting the crucial role of molecular weight in penetration efficiency. Soil degradation tests further confirmed the excellent biodegradability of CP3-GTE-tanned leather. These results demonstrate that epoxidized corncob polysaccharides are effective, eco-friendly tanning agents, offering a promising strategy for sustainable leather processing.