聚乳酸基静电纺丝光催化复合膜的制备及其应用

Preparation and Application of Polylactic Acid-Based Electrospun Photocatalytic Composite Films

摘要:

为解决传统聚乳酸(polylactic acid,PLA)包装材料的性能缺陷,以及减少芒果在运输和贮藏过程中因乙烯催熟变质而产生的经济损失问题,采用静电纺丝技术,引入壳聚糖(chitosan,CS)以改善PLA的固有缺陷,并负载不同比例TiO₂纳米颗粒,制备了系列PLA/CS/nTiO₂纳米纤维复合膜。通过扫描电镜、傅里叶红外光谱、X射线衍射光谱对复合膜微观结构进行表征,系统探究了其力学性能、阻隔性能、疏水性能；结合光催化实验研究复合膜对乙烯的清除能力,并开展为期10d的芒果保鲜实验,通过测定贮藏期间果实的失重率、硬度、色泽、总酚含量及丙二醛(MDA)积累量,评估该复合膜的保鲜效果。研究结果表明,与纯PLA膜相比,当TiO₂添加量(质量分数)为4%时,复合膜综合性能较优:拉伸强度与断裂伸长率分别提升至7.93MPa和55.74%,同时具备适宜的水蒸气、氧气阻隔性能与疏水特性。其中优化组复合膜的乙烯清除率可达67.6%,与无膜处理相比,复合膜能有效降解芒果贮藏期间产生的乙烯,显著延缓芒果失重与硬度下降,抑制表皮色泽劣变,减少总酚的消耗,降低MDA积累量,从而有效延缓了芒果的腐败进程。希望研究可为果蔬活性保鲜包装材料的研制提供新的技术方案。

Abstract:

To address the performance limitations of traditional polylactic acid (PLA) packaging materials, as well as to reduce the economic losses caused by ethylene-induced over-ripening and spoilage of mangoes during transportation and storage, a series of PLA/CS/nTiO₂ nanofibrous composite films were fabricated via electrospinning. In this process, chitosan (CS) was incorporated to ameliorate the inherent defects of the PLA matrix, while TiO₂ nanoparticles with different loading ratios were introduced as functional fillers. The microstructure of the composite films was characterized via scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction, followed by systematic evaluations of its mechanical properties, barrier performance, and hydrophobicity. Subsequently, photocatalytic experiments were conducted to investigate its ethylene degradation capability, and a 10-day mango preservation trial was carried out. During the storage period, the preservation effect of the composite films was evaluated by monitoring the fruit weight loss rate, firmness, peel color, total phenolic content, and malondialdehyde (MDA) accumulation. The results demonstrated that compared with pure PLA film, the composite film with 4% TiO₂ exhibited the optimal comprehensive performance. Its tensile strength and elongation at break increased to 7.93MPa and 55.74%, respectively, accompanied by suitable water vapor and oxygen barrier properties as well as favorable hydrophobicity. Notably, this optimal formulation achieved an ethylene removal rate of 67.6%, compared with no-film treatment, which could effectively degrade the ethylene generated during mango storage. It significantly delayed the weight loss and firmness decline of mangoes, inhibited peel color deterioration, reduced the consumption of total phenolic, and lowered MDA accumulation, thereby retarding the spoilage process of mangoes effectively. This work aimed to provide a novel technical solution for the development of active food packaging for fruits and vegetables.