Preparation of Lignin Derivatives Substituted with 3,4-dihydroxybenzylamine and Their Application as a Biomaterial with Antioxidant and Ultraviolet Light Blocking Properties

초록

Epoxy kraft lignin (EKL) was prepared by substituting the hydroxyl groups of kraft lignin with epoxide groups. Subsequently, 3,4-dihydroxybenzylamine (DHBA) was introduced to the prepared EKL substituted with DHBA (EKL-DHBA) to impart antioxidant and ultraviolet (UV) light blocking properties. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and 1H nuclear magnetic resonance spectroscopy confirmed that the DHBA moiety had been grafted successfully onto the lignin macromolecule. Additionally, 31P NMR analysis revealed that EKL-DHBA had a higher content of phenolic hydroxyl groups than KL, owing to catechol structure substitution. EKL-DHBA/polyvinyl alcohol (PVA) films were prepared and their antioxidant and UV blocking properties were investigated. The antioxidant activity of the film prepared adding 1 wt.% of EKL-DHBA was 93.15%, which was higher than that of ethanol soluble kraft lignin (EL). Furthermore, the EKL-DHBA/PVA film exhibited excellent UV blocking properties of approximately 96.75% –86.12% in UV-B (280-320 nm) and 86.12% in UV-A (280-400 nm) regions. Thus, the UV blocking properties of the EKL-DHBA/PVA film was much higher than that of EL or PVA film. Therefore, EKL-DHBAs with excellent antioxidant and UV blocking properties are potential additives to composite biomaterials. © 2022 Korean Technical Assoc. of the Pulp and Paper Industry. All rights reserved.

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