Lignin-based composites with enhanced mechanical properties by acetone fractionation and epoxidation modification

Epoxy resin is widely used in various fields of the national economy due to its excellent chemical and mechanical properties. Lignin is mainly derived from ligno-celluloses as one of the most abundant renewable bioresources. Due to the diver-sity of lignin sources and the complexity as well as heterogeneity of its structure, the value of lignin has not been fully realized. Herein, we report the utilization of industrial alkali lignin for the preparation of low-carbon and environmentally friendly bio-based epoxy thermosetting materials. Specifically, epoxidized lignin with substituted petroleum-based chemical bisphenol A diglycidyl ether (BADGE) in various proportions was cross-linked to fabricate thermosetting epoxies. The cured thermosetting resin revealed enhanced tensile strength (4.6 MPa) and elon-gation (315.5%) in comparison with the common BADGE polymers. Overall, this work provides a practicable approach for lignin valorization toward tailored sus-tainable bioplastics in the context of a circular bioeconomy.

Automated summary

In this study, industrial alkali lignin was used to prepare low-carbon and environmentally friendly bio-based epoxy thermosetting materials, resulting in improved tensile strength and elongation compared to common BADGE polymers. This work offers a practical approach for the valorization of lignin towards sustainable bioplastics in a circular bioeconomy context.