目的 研发出一种具有优异氧气阻隔性能的柔性薄膜，其在食品包装领域具有良好的应用前景。方法 以具有生物降解性能的聚乙烯醇(PVA)为成膜基材，镁铝层状双金属氢氧化物(MgAl-LDH)为改性剂，柠檬酸为交联剂，采用流延法制备出具有优异气体阻隔性能的PVA/MgAl-LDH复合薄膜。结果 随着柠檬酸的含量的增加，复合薄膜的亲水性能逐渐增加，阻隔性能逐渐下降;随着复合薄膜中MgAl-LDH的含量的增加，复合薄膜的疏水性能和阻隔性能逐渐提高。当复合薄膜中MgAl-LDH的质量分数为1.5%时，薄膜的力学性能最好，抗拉强度为42 MPa，断裂伸长率为16.7%，此MgAl-LDH质量分数下薄膜的气体阻隔性能也最优异，气体透过量为16 mL/(m².24 h.0.1 MPa)。结论 柠檬酸的引入增加了薄膜内部亲水基团的数量，提升了复合薄膜的亲水性能。MgAl-LDH可以减少PVA薄膜内部自由体积，提升PVA薄膜的力学性能和阻隔性能。

The work aims to develop a flexible film with excellent oxygen barrier performance and good application prospects in the field of food packaging. The PVA/MgAl-LDH composite film with excellent gas barrier performance was prepared by the casting method with biodegradable polyvinyl alcohol (PVA) as the film-forming substrate, magnesium-aluminum layered bimetallic hydroxide (MgAl-LDH) as the modifier, and citric acid as the cross-linking agent. The experimental results showed that with the increase of citric acid content, the hydrophilic property of the composite film gradually increased and the barrier performance decreased gradually. With the increase of MgAl-LDH content in the composite film, the hydrophobic property and barrier property of the composite film gradually increased. When the content of MgAl-LDH in the composite film was 1.5%, the mechanical properties of the film were the best, with a tensile strength of 42 MPa and an elongation at break of 16.7%. The gas barrier performance of the film with this MgAl-LDH content was also the best, with a gas permeability of 16 mL/(m2.24 h.0.1 MPa). In addition, the introduction of citric acid increases the number of hydrophilic groups inside the film, and the hydrophilic properties of the composite film are enhanced. MgAl-LDH can reduce the free volume inside the PVA film and enhance the mechanical and barrier properties of the PVA film.