Assembly Mechanism of Cellulose Nanocrystalline/Layered Bimetallic Hydroxide With Polylactic Acid and Its Enhancement Mechanism

ABSTRACT As global concern over plastic pollution grows, the development of biodegradable high‐performance materials has become an urgent necessity to address the environmental crisis. Poly(lactic acid) (PLA), a fully biodegradable polyester, has attracted substantial research interest stemming from its notable biocompatibility and processability. Nevertheless, its inherently brittle nature and limited thermal stability restrict its broader application. In this study, cellulose nanocrystal (CNC) was surface‐modified with a silane coupling agent (KH‐550). Magnesium‐aluminum‐based layered double hydroxide (LDH) was synthesized and its properties were optimized through sodium stearate surface modification and sodium dodecyl sulfate intercalation modification. CNC and LDH were co‐introduced into a PLA matrix via a solution blending method to prepare composite membrane materials. The results showed that the synergistic effect of 3 wt% Si CNC I and 3 wt% SSDLDH increased the tensile strength of the composite material to 96.8 MPa and reduced the water vapor permeability by 38.9%. This study systematically revealed the modification strategies of CNC and LDH and their synergistic effects on the performance of PLA, providing a theoretical basis and technical pathways for the development of high‐performance biodegradable composite materials. It holds significant scientific value for promoting the application of green materials in fields such as packaging and biomedicine.