Molecularly Engineered Lignin-Derived Additives Enable Fire-Retardant, UV-Shielding, and Mechanically Strong Polylactide Biocomposites

• Published in: Biomacromolecules Vol. 22; no. 4; pp. 1432 - 1444
• Main Authors: Yang, Haitang, Shi, Bingbing, Xue, Yijiao, Ma, Zhewen, Liu, Lina, Liu, Lei, Yu, Youming, Zhang, Zhanying, Annamalai, Pratheep K, Song, Pingan
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 12.04.2021
• Subjects: additives; biocomposites; electronics; lignin; modulus of elasticity; polylactic acid; polymerization; strength (mechanics); sustainable development; wastes
• ISSN: 1525-7797; 1526-4602; 1526-4602
• DOI: 10.1021/acs.biomac.0c01656

From a perspective of sustainable development and practical applications, there has been a great need for the design of advanced polylactide (PLA) biocomposites that are flame-retardant, ultraviolet (UV)-resistant, and mechanically strong by using biomass-derived additives. Unfortunately, the achievement of a desirable performance portfolio remains unsatisfactory because of improper design strategies. Herein, we report the design of lignin-derived multifunctional bioadditives (TP-g-lignin) with tunable chemical compositions through graft polymerization of a phosphorus-/nitrogen-containing vinyl monomer (TP). Our results show that the incorporation of 5.0 wt % of TP-g-lignin (at a lignin-to-TP ratio of 1:4 by mass) enables PLA to achieve a desirable flame retardancy rating meeting the UL-94 V-0 industrial standard requirements. Meanwhile, the final PLA composite exhibits an exceptional UV-shielding capability. Moreover, with 5.0 wt % of the bio-derived additive, the elastic modulus of PLA is increased by ∼26%, while mechanical strength is fully retained due to engineered favorable interfaces. This work offers an innovative and sustainable strategy for creating bio-based multifunctional additives by using industrial lignin waste and further the application of PLA in the areas of packaging, fabrics, electronics, automobiles, etc.