As the most extensively researched thermoplastic aliphatic polyester, poly (lactic acid) (PLA) derived from renewable resources has shown it tremendous potential at replacing the petroleum-based polymers in many fields. The greatest challenge hindering the use of PLA is considered as its poor toughness. In terms of reproducible processes and products, cellulose has been applied to the PLA matrix as reinforcing fillers but the poor compatibility due to the inherent hydrophilicity of cellulose and hydrophobic nature of PLA is troubling. To solve this issue, we carried out an effective water-based method to render the cellulose surface with high carboxylic group content through the esterification of hydroxyl groups with citric acid in a solid phase reaction to strengthen the hydrogen bonding interaction with PLA. Consequently, the modified cellulose showed good dispersion in PLA matrix. The resulting flexural properties of PLA composites incorporated by the citric acid-modified cellulose and its fibrillated form as fillers were improved compared to those of the pristine PLA resin. The potential nucleating function of the modified cellulose was discussed and the filler proportion in the composite was optimized. Because of the well-established processing technique, we believe that citric acid-modified cellulose has an immense potential as a sustainable and cost-effective reinforcing filler for PLA, as a representative of bio-based polyesters.

作为研究最广泛的热塑性脂族聚酯，从可再生资源中衍生出来的聚乳酸（PLA）已显示出在许多领域取代石油基聚合物的巨大潜力。阻碍PLA使用的最大挑战是韧性差。在可重复生产的方法和产品方面，纤维素已作为增强填料应用于PLA基质，但由于纤维素固有的亲水性和PLA的疏水性，其相容性差。为了解决这个问题，我们进行了有效的水基方法，通过固相反应中羟基与柠檬酸的酯化作用，使纤维素表面具有高羧基含量，从而增强了与PLA的氢键相互作用。所以，改性纤维素在PLA基质中显示出良好的分散性。与原始的PLA树脂相比，由柠檬酸改性的纤维素及其原纤化形式作为填料掺入的PLA复合材料的抗弯性能得到了改善。讨论了改性纤维素的潜在成核功能，并优化了复合材料中填料的比例。由于成熟的加工技术，我们相信柠檬酸改性的纤维素作为生物基聚酯的代表，作为PLA的可持续且具有成本效益的增强填料具有巨大的潜力。讨论了改性纤维素的潜在成核功能，并优化了复合材料中填料的比例。由于成熟的加工技术，我们相信柠檬酸改性的纤维素作为生物基聚酯的代表，作为PLA的可持续且具有成本效益的增强填料具有巨大的潜力。讨论了改性纤维素的潜在成核功能，并优化了复合材料中填料的比例。由于成熟的加工技术，我们相信柠檬酸改性的纤维素作为生物基聚酯的代表，作为PLA的可持续且具有成本效益的增强填料具有巨大的潜力。