Department of Food Science and Technology, Faculty of Agriculture and Natural resources, University of Mohaghegh Ardabili, Ardabil, Iran.
Department of Chemical Engineering, Faculty of Engineering, University of Bonab, Bonab, Iran.
Int J Biol Macromol. 2018 Mar;108:863-873. doi: 10.1016/j.ijbiomac.2017.10.185. Epub 2017 Nov 11.
In this research, a novel carboxymethyl cellulose (CMC)-based nanocomposite films containing sodium montmorillonite (MMT) (5%wt) and zinc oxide (ZnO) (1, 2, 3 and 4%wt) nanoparticles (NPs) were fabricated via casting method. The results revealed that addition of NPs decreased water vapor permeability of the films by about 53%, while moisture content, density and glass transition temperature increased. The nanomaterials enhanced resistance of the nanocomposites against tensile stress at the expense of elongation at break. Nano-ZnO was very effective than nanoclay in UV-light blocking (99% vs. 60%) associated with sacrificing the films transparency. Formation of hydrogen bonds between the hydroxyl groups of CMC and MMT was evidenced by FTIR spectroscopy. According to the XRD analysis, clay nanolayers formed an exfoliated structure in the nanocomposites, whereas ZnO NPs raised crystallinity. SEM micrographs showed well-dispersed MMT and ZnO NPs through the films surface. Antibacterial test showed that vulnerability of Gram-positive S. aureus toward ZnO NPs was more than that of Gram-negative E. Coli. In conclusion, simultaneous incorporation of MMT and ZnO NPs improved the functional characteristics of CMC film and extended the potential for food packaging applications.
在这项研究中，通过浇注法制备了一种新型的羧甲基纤维素（CMC）基纳米复合材料薄膜，其中含有钠蒙脱石（MMT）（5wt%）和氧化锌（ZnO）（1、2、3 和 4wt%）纳米粒子（NPs）。结果表明，纳米粒子的添加使薄膜的水蒸气透过率降低了约 53%，而水分含量、密度和玻璃化转变温度增加。纳米材料提高了纳米复合材料对拉伸应力的抵抗力，但其断裂伸长率降低。纳米 ZnO 比纳米黏土更有效地阻挡紫外线（99%对 60%），同时牺牲了薄膜的透明度。FTIR 光谱证明了 CMC 和 MMT 羟基之间形成氢键。根据 XRD 分析，黏土纳米层在纳米复合材料中形成了剥离结构，而 ZnO NPs 提高了结晶度。SEM 显微照片显示，MMT 和 ZnO NPs 在薄膜表面上分散良好。抗菌试验表明，革兰氏阳性金黄色葡萄球菌对 ZnO NPs 的敏感性高于革兰氏阴性大肠杆菌。总之，同时掺入 MMT 和 ZnO NPs 提高了 CMC 薄膜的功能特性，并扩展了其在食品包装应用中的潜力。
