It is a great challenge to develop a feasible strategy for reconciling barrier performance and mechanical ductility of environmentally friendly poly(lactic acid) (PLA) in the application of packaging industry. In the current study, the combination of manipulating the amorphous chain entanglement network of PLA and constructing “dual barrier walls” of highly aligned GONSs and well-defined PLA crystals simultaneously enhanced barrier properties and ductility of PLA nanocomposite films via “biaxial stretching-constrained annealing” method. The intense extensional field during biaxial stretching induced highly aligned GONSs as the first barrier wall and regulated the amorphous chain entanglement network. Constrained annealing promoted the growth and perfection of PLA crystals as the second effective barrier wall and strengthened amorphous chain entanglement network to some extent. More interestingly, GONSs were first verified as contributors to stabilize the enhanced amorphous chain entanglement network of PLA and benefited for the mechanical ductility of PLA nanocomposite films. As a result, this synergetic structure manifested excellent comprehensive ability in ameliorating the intrinsic drawbacks of brittle and poor barrier PLA films, exhibiting low oxygen permeability coefficient of 0.712 × 10⁻¹⁴ cm³ cm cm⁻² s⁻¹ Pa⁻¹, excellent ductility with elongation at break of 147.8%, high yield strength of 83.1 MPa and good dimensional stability with deformation ratio of as low as 3%. The as-prepared PLA nanocomposite films with excellent comprehensive properties hold great potential prospects in the application of packaging industry. The methodology proposed here opens up a new avenue to fabricate environmentally friendly PLA films for promoting the sustainable development of packaging industry.

在包装行业的应用中，开发一种可行的策略来协调环保聚乳酸（PLA）的阻隔性能和机械延展性是一个巨大的挑战。在目前的研究中，操纵 PLA 的无定形链缠结网络与构建高度排列的 GONS 和明确定义的 PLA 晶体的“双重屏障墙”相结合，通过“双轴拉伸约束退火”同时增强了 PLA 纳米复合膜的阻隔性能和延展性“ 方法。双轴拉伸过程中的强拉伸场诱导高度排列的 GONS 作为第一屏障并调节无定形链缠结网络。约束退火促进了PLA晶体作为第二层有效屏障的生长和完善，并在一定程度上加强了非晶链缠结网络。更有趣的是，GONS 首次被证实是稳定 PLA 增强的非晶链缠结网络的贡献者，并有利于 PLA 纳米复合薄膜的机械延展性。因此，这种协同结构在改善 PLA 薄膜脆性和阻隔性差的固有缺点方面表现出优异的综合能力，氧渗透系数低，为 0.712 × 10^-14  cm ³  cm cm ^-2 s ^-1  Pa ^-1，良好的延展性，断裂伸长率为147.8%，屈服强度高达83.1 MPa，尺寸稳定性好，变形率低至3%。所制备的PLA纳米复合薄膜具有优异的综合性能，在包装行业的应用前景广阔。这里提出的方法为制造环保型PLA薄膜开辟了一条新途径，以促进包装行业的可持续发展。