Structural Characterization of Acid DES-Modified Alkaline Lignin and Evaluation of Antioxidant Properties

Lignin is an abundant and environmentally friendly biopolymer that contains a large number of phenolic hydroxyl functional group. In this paper, alkaline lignin was modified using different acidic DES (choline chloride/p-toluenesulfonic acid choline chloride/lactic acid) at 130 ℃ (TC-lignin LC-lignin) the conformational relationship between products antioxidant activity investigated. characterized by 31P NMR, gel permeation chromatography (GPC) Fourier transform infrared spectroscopy (FT-IR), its evaluated. The results showed formed relatively homogenous dispersions were low molecular weight high content groups (e.g., TC-lignin, aliphatic-OH: 3.52 mmol/g, G-OH: 4.18 Mw: 3726, Mn: 2053, PDI: 1.81). (free radical scavenging rate, 90.35%) TC-lignin somewhat higher than LC-lignin 89.12%) both commercially available BHT 88.79%). More specifically, we discussed possible mechanisms reactions model substances in DPPH solutions. addition, has excellent UV-blocking capacity due to specific phenyl propane structure. A simple method proposed for modification industrial make it suitable use as UV-resistant product.