Possible use of corn starch as tanning agent in leather industry: Controlled (gradual) degradation by H2O2

Abstract

High molecular weight/size and poor solubility of native starch seems to be preliminary drawbacks in its possible use in leather processing as a tanning/retanning agent. For this purpose, firstly the native starch which has too large molecular size to penetrate between skin fiber matrix was oxidized with H₂O₂ in different molar ratios for disintegrating into appropriate molecular size that can be used in tanning process. Then, the product yields, water solubilities and degree of substitutions of oxidized starches were determined. Also, the oxidized starch samples were characterized by Fourier Transforms Infrared (FT-IR) Spectroscopy, Gel Permeation Chromatography (GPC) and Proton Nuclear Magnetic Resonance (¹H NMR) Spectroscopy. According to the GPC results, the oxidized starch samples which their molecular weights were reduced for penetrating into skin fibers were selected and they were used in tanning process of goat skins. The tanning effects of selected oxidized starches were evaluated according to shrinkage temperatures, filling coefficients and Scanning Electron Microscopy (SEM) analysis. From the results, it was revealed that the native corn starch can be oxidized with H₂O₂ in a controlled manner and oxidized starch can be utilized as a tanning/retanning agent in leather making.

Keywords: Leather; Oxidation; Peroxide; Starch; Tanning.