Abstract:
Bio-based and biodegradable polyhydroxyalkanoates (PHAs) have great potential as sustainable packaging materials. The incorporation of zinc oxide nanoparticles (ZnO NPs) could further improve their functional properties by providing enhanced barrier and antimicrobial properties, although current literature lacks details on how the characteristics of ZnO influence the structure-property relationships in PHA/ZnO nanocomposites. Therefore, commercial ZnO NPs with different morphologies (rod-like, spherical) and silane surface modification are incorporated into poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) via extrusion and compression molding. All ZnO NPs are homogeneously distributed in the PHBHHx matrix at 1, 3 and 5 wt.%, but finer dispersion is achieved with modified ZnO. No chemical interactions between ZnO and PHBHHx are observed due to a lack of hydroxyl groups on ZnO. The fabricated nanocomposite films retain the flexible properties of PHBHHx with minimal impact of ZnO NPs on crystallization kinetics and the degree of crystallinity (53 to 56%). The opacity gradually increases with ZnO loading, while remaining translucent up to 5 wt.% ZnO and providing an effective UV barrier. Improved oxygen barrier and antibacterial effects against S. aureus are dependent on the intrinsic characteristics of ZnO rather than its morphology. We conclude that PHBHHx retains its favorable processing properties while producing nanocomposite films that are suitable as flexible active packaging materials.
摘要:
生物基和可生物降解的聚羟基链烷酸酯(PHAs)作为可持续包装材料具有巨大的潜力。氧化锌纳米颗粒(ZnONPs)的掺入可以通过提供增强的屏障和抗菌性能来进一步改善其功能特性,尽管目前的文献缺乏有关ZnO特性如何影响PHA/ZnO纳米复合材料结构-性能关系的详细信息。因此,具有不同形貌的商业ZnONPs(棒状,球形)和硅烷表面改性通过挤出和压塑结合到聚(3-羟基丁酸酯-共-3-羟基己酸酯)(PHBHHx)中。所有ZnONP均以1、3和5重量%均匀分布在PHBHHx基质中。%,但是用改性的ZnO实现了更精细的分散。由于在ZnO上缺少羟基,在ZnO和PHBHHx之间没有观察到化学相互作用。所制备的纳米复合薄膜保留了PHBHHx的柔性性能,而ZnONP对结晶动力学和结晶度的影响最小(53%至56%)。不透明度随着ZnO负载而逐渐增加,同时保持半透明高达5wt。%ZnO并提供有效的UV屏障。针对金黄色葡萄球菌的改进的氧屏障和抗菌作用取决于ZnO的固有特性而不是其形态。我们得出的结论是,PHBHHx保留了其良好的加工性能,同时生产了适合作为柔性活性包装材料的纳米复合膜。