A Chemical Anchoring Strategy for Building Robust Interlocking Interfaces in Bamboo Fiber/PLA Biocomposites with Synergistic Toughness and UV Shielding

The development of high-performance biocomposites is crucial for advancing sustainability, in the context of fossil resource shortages and environmental pollution. In this study, bamboo fiber (BF) was incorporated into poly(lactic acid) (PLA) and the interface was modified via the strategy of chemical anchoring and in situ construction to overcome the limitations of PLA in toughness and weather resistance. By this means, chemically reactive anchor points were established on the BF surface to enable the in situ growth of ZnO nanoparticle arrays. Consequently, the BF acquired a hierarchical surface featuring ZnO nanoparticle arrays, leading to a nanoscale interlocking interface with the PLA matrix. This interlocked interface was reinforced by firm interfacial interactions with significantly boosted anchoring points, facilitating the stress transfer and energy dissipation. Therefore, the resultant BF/PLA composites demonstrated significantly enhanced impact strength, which was 151.3% higher than neat PLA and 64.4% higher than the unmodified BF/PLA composite. Moreover, the ZnO nanoparticles endowed the composite effective shielding across the entire UVA and UVB spectrum. This work provides a feasible strategy for designing high-performance, functionalized, and environmentally friendly composites.