The application of flexible polymer nanocomposites for food packaging to inactivate microorganisms associated with foods is the demand of the present-day food industry to assure quality throughout the packaging operation. The utilization of polyvinyl alcohol (PVA) assisted zinc oxide nanocomposite for food stuff packaging has been very attractive in the recent past. Nanostructured ZnO was synthesized at optimized pH (10.5) from different ratios of zinc acetate and Moringa oleifeira leaf extract (1:7, 1:3, 1:1 and 3:1). ZnO coated polyvinyl alcohol (ZnO/PVA) nanocomposites were prepared from 5, 9, 13 and 16% by wt of ZnO and PVA using solution casting method. The thermal stability of ZnO synthesized with 1:1 ratio at pH 10.5 was investigated with TGA/DTA. The analytical techniques such as X-ray diffraction (XRD), ultra-violate visible analysis (UV-Vis), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscope (SEM) were used for the characterization of the synthesized ZnO and ZnO/PVA nanocomposites (NCs). The antibacterial activity of the synthesized ZnO and ZnO/PVA NCs were evaluated against gram negative E. coli and gram positive S. aureus bacteria. The electrochemical stability of ZnO/PVA NCs was also investigated by cyclic voltammetric (CV) method. The thermogram of ZnO indicated that the oxide was found to be stable even beyond 500°C. The SEM analysis revealed rod shaped morphology for synthesized ZnO from 1:1 ratio at pH 10.5. But the nanocomposite prepared with 5% of ZnO of (1:1) at the same pH exhibited uniformly dispersed rod-shaped particle on the surface as well as in matrix of polyvinyl alcohol film. According to XRD result, ZnO synthesized with more percentage of plant extract resulted in the small size crystallites while that with low percentage of plant extract resulted in the larger crystallite size. The antibacterial inhibition efficiency of ZnO/PVA NCs was better and found to increase with increase in the amount of ZnO.

中文翻译：

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辣木含水提取物模板合成ZnO和ZnO / PVA纳米复合材料的抗菌和电化学活性

在食品包装中应用柔性聚合物纳米复合材料以灭活与食品有关的微生物是当今食品工业在整个包装过程中确保质量的要求。近年来，聚乙烯醇（PVA）辅助的氧化锌纳米复合材料在食品包装中的应用非常吸引人。由乙酸锌和辣木的不同比例在最佳pH（10.5）下合成了纳米结构的ZnO。叶提取物（1：7、1：3、1：1和3：1）。使用溶液流延法，由5、9、13和16 wt％的ZnO和PVA制备ZnO涂覆的聚乙烯醇（ZnO / PVA）纳米复合材料。用TGA / DTA研究了1：1比例合成的ZnO在pH 10.5时的热稳定性。使用X射线衍射（XRD），紫外可见分析（UV-Vis），傅立叶变换红外光谱（FTIR）和扫描电子显微镜（SEM）等分析技术来表征合成的ZnO和ZnO / PVA纳米复合材料（NCs）。评估了合成的ZnO和ZnO / PVA NCs对革兰氏阴性大肠杆菌和革兰氏阳性金黄色葡萄球菌的抗菌活性。菌。还通过循环伏安法（CV）研究了ZnO / PVA NCs的电化学稳定性。ZnO的热分析图表明该氧化物甚至在超过500℃时也是稳定的。SEM分析显示，在pH 10.5时，1：1比例的合成ZnO呈棒状形态。但是，在相同的pH条件下，用5％的ZnO（1：1）制备的纳米复合材料在聚乙烯醇薄膜的表面和基质中均显示出均匀分散的棒状颗粒。X射线衍射结果表明，ZnO含量较高的植物提取物所合成的晶粒尺寸较小，而ZnO含量较低的植物所产生的晶粒尺寸较大。ZnO / PVA NCs的抑菌效果更好，并且随ZnO含量的增加而增加。