Abstract For the last few decades, the application of biopolymers such as poly(lactic acid, PLA) as an alternative to synthetic polymers in the packaging industry is in great demand. However, to rival the traditional polymers, the barrier properties and antimicrobial activities of PLA need to be adapted to the food packaging requirements. The purpose of this research was to compare the impact of thin-film fabrication techniques in combination with different contents of cellulose nanocrystals (CNCs) (1–5 wt%) on the barrier and antimicrobial properties of PLA films. The nanocomposite thin films were manufactured via solvent casting and spin-coating techniques. The spin-coating method has been employed for the first time in this work to prepare nanocomposite thin films with a thickness of ˂ 0.2 mm. The nanocomposite films were tested for surface morphology, degree of crystallinity, water vapor permeability, contact angle, and antimicrobial properties. Scanning electron microscopy (SEM) micrographs revealed the strong tendency of CNCs to establish microscale aggregates, however, a high drying rate in the spin-coating method decreases the self-assembly in CNCs. Thus, a significantly higher degree of crystallinity and glass transition temperature were observed in spin-coated films due to a more uniform dispersion of CNCs in PLA. Higher contact angle and lower water vapor transfer rate in spin-coated samples confirmed the lower hydrophilicity character of spin-coated thin films. Two separate assays were employed for evaluating the anti-microbial activity of PLA on the foodborne pathogens. The results showed that the film manufacturing technique and CNC concentration have a strong influence on microbial reduction.

中文翻译：

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旋涂法改善了由聚乳酸和纤维素纳米晶体获得的薄膜的性能特征

摘要 在过去的几十年里，聚乳酸、PLA 等生物聚合物作为合成聚合物的替代品在包装行业的应用需求很大。然而，为了与传统聚合物竞争，PLA 的阻隔性能和抗菌活性需要适应食品包装要求。本研究的目的是比较薄膜制造技术与不同含量的纤维素纳米晶体 (CNCs) (1–5 wt%) 相结合对 PLA 薄膜的阻隔和抗菌性能的影响。纳米复合薄膜是通过溶剂浇铸和旋涂技术制造的。在这项工作中首次采用旋涂方法制备了厚度为˂ 0.2 mm的纳米复合薄膜。测试纳米复合薄膜的表面形态、结晶度、水蒸气渗透性、接触角和抗菌性能。扫描电子显微镜 (SEM) 显微照片显示 CNCs 建立微型聚集体的强烈趋势，然而，旋涂方法中的高干燥速率降低了 CNCs 的自组装。因此，由于 CNC 在 PLA 中的分散更均匀，因此在旋涂膜中观察到显着更高的结晶度和玻璃化转变温度。旋涂样品中较高的接触角和较低的水蒸气转移率证实了旋涂薄膜的亲水性较低。使用两种单独的测定来评估 PLA 对食源性病原体的抗微生物活性。