Synthesis of lignin-modified cellulose nanocrystals with antioxidant activity via Diels-Alder reaction and its application in carboxymethyl cellulose film

Liangliang An; Jiansong Chen; Ji Won Heo; Jin Ho Bae; Hanseob Jeong; Yong Sik Kim

doi:10.1016/j.carbpol.2021.118651

Synthesis of lignin-modified cellulose nanocrystals with antioxidant activity via Diels-Alder reaction and its application in carboxymethyl cellulose film

Carbohydr Polym. 2021 Nov 15:274:118651. doi: 10.1016/j.carbpol.2021.118651. Epub 2021 Sep 9.

Authors

Liangliang An¹, Jiansong Chen¹, Ji Won Heo¹, Jin Ho Bae¹, Hanseob Jeong², Yong Sik Kim³

Affiliations

¹ Department of Paper Science & Engineering, College of Forest and Environmental Sciences, Kangwon National University, Chuncheon 24341, Republic of Korea.
² Forest Industrial Materials Division, Forest Products and Industry Department, National Institute of Forest Science, Seoul 02455, Republic of Korea.
³ Department of Paper Science & Engineering, College of Forest and Environmental Sciences, Kangwon National University, Chuncheon 24341, Republic of Korea. Electronic address: yongsikk@kangwon.ac.kr.

PMID: 34702470
DOI: 10.1016/j.carbpol.2021.118651

Abstract

Multifunctional polymers derived from renewable organic substances have received significant attention. In this work, the Diels-Alder "click" reaction was used to synthesize a renewable copolymer with the mechanical strength of cellulose nanocrystals (CNCs) and the natural antioxidant activity of lignin. Chemical structural analysis and molecular weight results confirmed that lignin was successfully attached to the CNCs. Phenolic hydroxyl groups were introduced into CNCs, resulting in good antioxidant activity with an IC₅₀ value of 1.49 mg/mL, although a slight decrease in the crystallinity index and thermal properties was observed. Additionally, carboxymethyl cellulose (CMC) films containing lignin-modified CNCs were prepared by solution casting. The lignin-modified CNCs endowed film with antioxidant activity and also contributed to increasing the tensile strength by 70%. This indicated that the lignin-modified CNCs with good antioxidant activities and mechanical strength have promising applications in multifunctional materials.

Keywords: Antioxidant; Cellulose nanocrystals; Lignin; Multifunctionality; Reinforcement; Thin film.