Oxidized Maltodextrin: A Novel Ligand for Aluminum–Zirconium Complex Tanning

Abstract

Hydrogen peroxide (H₂O₂) oxidized maltodextrin was prepared as the ligand for aluminum–zirconium complex tanning. The effects of catalyst dosage, initiation temperature, and H₂O₂ dosage on maltodextrin oxidation were investigated. FT-IR analysis demonstrated that carboxyl groups were successfully introduced into oxidized maltodextrin. The carboxyl content and degradation degree of oxidized maltodextrin increased with the increase of H₂O₂ dosage.  Maltodextrin oxidized by 40% H₂O₂ and 0.015% Cu–Fe catalyst at an initiation temperature of 70°C (OD-40) with moderate carboxyl group (6.75 mmol/g) and molecular weight (M_w 450) promoted the penetration and fixation of aluminum–zirconium salts in leather and showed better tanning performance, such as hydrothermal stability and porosity of leather, than traditional citric acid ligand.