Insight into the complex coupling agents on thermal, mechanical, and barrier properties of lignin‐poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) biocomposites

Abstract Biodegradable polymers, including poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) (PHBH), can replace traditional plastics to effectively target microplastic pollution; however, their high cost limits their application. In this study, lignin modified with the complex coupling agents was prepared and incorporated into PHBH to reduce its cost and improve the compatibility of composites. The results showed lignin modified with the complex coupling agents was dispersed well in the PHBH matrix. Compared to other composites, lignin‐PHBH biocomposites modified with maleic anhydride and KH550 had better thermal stability, mechanical and barrier properties due to collaborative modification. Moreover, lignin‐PHBH biocomposites showed the excellent UV resistance and antioxidant activity. The obtained results revealed that using the complex coupling agent was a feasible method to improve the properties of biocomposites.