Inspired by the lignin-cellulose network in natural wood, we developed a strategy to produce cellulose nanofibril (CNF) composite films using lignin nanoparticles (LNPs) with varied contents of phenolic hydroxyl (Ph-OH) groups as a reinforcing agent. Regulated LNPs with lower molecular weight, higher Ph-OH content, and uniform morphology were successfully prepared by phenolation and anti-solvent precipitation. CNFs mixed with phenolated LNPs of high Ph-OH content (8.23 mmol/g) exhibited a higher tensile strength (∼190 MPa), increased toughness (∼15 MJ/m³), and enhanced UV-blocking ability (∼99%) compared to lignin-free CNFs and CNFs composites with lower Ph-OH content. Thus, hydrogen bonds between Ph-OH groups on lignin and hydroxyl groups on CNFs are vital for enhancing the mechanical strength of composite films. Similar enhanced mechanical properties were found by adding phenolated LNPs into polyvinyl alcohol as a fortifier. This study provides novel insights into producing lignin-reinforced cellulose composite films with UV shielding, thermal stability, and biodegradability.

受天然木材中木质素-纤维素网络的启发，我们开发了一种使用具有不同酚羟基 (Ph-OH) 基团含量的木质素纳米粒子 (LNP) 作为增强剂来生产纤维素纳米原纤维 (CNF) 复合薄膜的策略。通过酚化和反溶剂沉淀成功制备了分子量较低、Ph-OH 含量较高、形态均匀的调控 LNP。与高 Ph-OH 含量（8.23 mmol/g）的酚化 LNP 混合的 CNF 表现出更高的拉伸强度（~190 MPa），增加的韧性（~15 MJ/m ³)，与不含木质素的 CNF 和具有较低 Ph-OH 含量的 CNF 复合材料相比，增强的紫外线阻挡能力 (~99%)。因此，木质素上的 Ph-OH 基团和 CNF 上的羟基之间的氢键对于提高复合薄膜的机械强度至关重要。通过在聚乙烯醇中添加酚化 LNP 作为强化剂，发现了类似的增强机械性能。本研究为生产具有紫外线屏蔽、热稳定性和可生物降解性的木质素增强纤维素复合薄膜提供了新的见解。