Enhanced mechanical and biodegradable properties of PBAT/lignin composites via silane grafting and reactive extrusion

Biodegradable polymers, including polybutylene adipate-co-terephthalate (PBAT), can replace traditional plastics to effectively target microplastic pollution; however, their high cost limits their application. In this study, vinyltrimethoxysilane (VTMS)-grafted lignin (VL) was prepared and incorporated into PBAT to reduce its cost and improve its mechanical properties while maintaining its biodegradability. Results show that the tensile strength, Young's modulus, and biodegradation efficiency of a PBAT/VL-30% composite increased by 200%, 151%, and 96%, respectively, compared with neat PBAT. VTMS grafting onto lignin thus improves the dispersion of lignin in PBAT; a network structure of PBAT and VL is formed via reactive extrusion. This work provides a theoretical basis for the design and development of low-cost, highly biodegradable PBAT composites.