This work aims to achieve the high-efficiency toughening of polylactic acid (PLA) via the fabrication of biomass-based composite fillers and their application in PLA modification. A hydrophobic acetylated lignin-attapulgite (ACL-ATP) composite filler was first prepared via solution blending, and then incorporated into PLA through melt blending to obtain PLA/ACL-ATP composites. Experimental results confirmed multiple interfacial interactions between ACL and ATP, such as hydrogen bonding, electrostatic forces, and cation-π interactions. The constructed hybrid structure not only reduced the intrinsic hydrophilicity of ATP, but also promoted its uniform dispersion in the PLA matrix. The introduction of ACL-ATP effectively triggered the energy dissipation mechanisms of PLA, leading to a dramatic 649% increment in the elongation at break for the PLA/ACL-ATP4 composite compared with neat PLA (6.8%). Microstructural characterization confirmed the uniform dispersion and good interfacial compatibility of ACL-ATP within the PLA matrix. Crystallization analysis revealed that ACL-ATP served as heterogeneous nucleation sites to refine crystallite size and improve the crystallization behavior of PLA. Meanwhile, the synergistic interaction between ACL and ATP enhanced the thermal stability of PLA, with the initial thermal decomposition temperature increasing from 304.8°C to 317.1°C. Collectively, these findings confirm that the ACL-ATP composite filler is a high-performance toughening modifier for PLA. The as-prepared filler can simultaneously improve the toughness, thermal stability, and crystallization performance of PLA. This research offers a viable route for engineering high-performance, sustainable PLA composites.
Ren et al. (Thu,) studied this question.