Influence of esterified kraft lignin as an interfacial compatibilizer on mechanical properties of acrylonitrile–butadiene–styrene/basalt fiber composites

This research investigates the enhancement effects of basalt fibers (BFs) and kraft lignin (KL) as natural additives on the mechanical properties of acrylonitrile–butadiene–styrene (ABS)‐based composites. Initially, BF was incorporated into ABS as a fiber reinforcement, and its mechanical properties were evaluated. It was observed that an increase in BF content in ABS led to an increase in the tensile strength while the impact strength tended to decrease. Subsequently, the potential of lignin or modified lignin as interfacial compatibilizers was assessed to improve the miscibility between ABS and BF. The modification of lignin was achieved via esterification by using esterifying agents (acetic anhydride [C2_Ac], propionic anhydride [C3_Pr], and butyric anhydride [C4_Bu]). At the optimal conditions (30 wt% of BF, 15phr of AcKL), the mechanical properties of ABS/BF/AcKL composite presented a 48.1% improvement in tensile strength and a 27.4% enhancement in impact strength compared to those of ABS/BF composite. The fracture surface analysis of the composite revealed that the esterified lignin enhances the compatibility between components, thereby filling the gaps present at the matrix‐fiber interface. These results suggest promising applications for multi‐component composite materials. Acrylonitrile butadiene styrene (ABS) composites were reinforced with basalt fiber (BF) and modified kraft lignin. Lignin was modified by adjusting the length of side‐chain (C2‐C4), and its function as an interfacial compatibilizer for ABS and BF was investigated. Incorporating modified lignin into ABS/BF composites enhanced their mechanical properties, indicating its effectiveness in improving compatibility.