Fully biobased, ultra-tough lignin/polybutylene succinate composites through reactive extrusion

The incorporation of lignin into polybutylene succinate (PBS) is considered as a green approach to enhance the mechanical properties, durability, and biodegradability of PBS. However, it often leads to only a limited improvement in the toughness of PBS due to the poor compatibility of lignin with PBS. Herein, we present a novel approach to prepare lignin reinforced PBS composites with fully biobased, ultra-tough and high tensile strength characteristics through reactive extrusion and mold-pressing methodology, involving lignin epoxy vitrimer (LEV), sebacic acid (SA) and PBS. The influences of the LEV content on the structure, mechanical property, morphology, reprocessability, self-healing, creep resistance characteristics of the resultant PBS/LEV composites were systematically investigated. The incorporation of LEV in PBS could induce unique dynamic microcrosslinked structure within PBS through dynamic transesterification reaction, which offered the resultant PBS/LEV composites with a extraordinary 18 times enhancement in elongation at break and a 13 times enhancement in toughness compared with that of pure PBS. Furthermore, the PBS/LEV composites exhibited excellent reprocessing, self-healing, creep resistance and UV resistance properties. The novel approach provides a potential avenue for enhancing the compatibility between lignin and PBS, which is beneficial for development new brand of lignin-containing fully biobased and biodegradable materials.