Abstract

Sodium montmorillonite organically modified by octadecylammonium (Np-Clay) and zinc oxide nanoparticles (Np-ZnO) were incorporated into chitosan (C) matrix in different proportions to evaluate its mechanical properties and antimicrobial activities. The composites were obtained by polymer intercalation method in solution using acetic acid (1% v/v) as solvent. The functional groups, thermic behavior and surface morphology of the chitosan film and of the composites prepared with different percentages of Np-Clay and Np-ZnO were characterized through Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The results showed that a combined effect of clay and zinc oxide increases significantly the mechanical properties of pure chitosan. FTIR results confirmed good compatibility among functional groups of chitosan, montmorillonite/metallic oxides. The Np-ZnO distribution became more uniform in chitosan films when the Np-clay was incorporated, thus, the Np-Clay compatibilizes the Np-ZnO with the chitosan and the mechanical properties improved and without affecting the antimicrobial activity of the films. The thermal degradation temperature of the chitosan did not change significantly with the addition of Np-Clay, but changes significantly with Np-ZnO addition. In antimicrobial test was found that the chitosan and Np-ZnO showed a synergistic effect against to Escherichia coli and Staphylococcus aureus. The addition of Np-ZnO and C-Clay in chitosan resulted in enhancement of mechanical and antimicrobial properties, turning this material prospective for food packaging applications.

Graphical Abstract

摘要

将十八碳铵（Np-Clay）和氧化锌纳米粒子（Np-ZnO）有机改性的蒙脱土钠按不同比例掺入壳聚糖（C）基质中，以评估其力学性能和抗菌活性。以乙酸（1％v / v）为溶剂，通过聚合物插层法在溶液中获得复合材料。通过傅立叶变换红外光谱（FTIR），热重分析（TGA），差示扫描量热法（FTIR）表征了壳聚糖膜以及不同比例的Np-Clay和Np-ZnO制备的复合材料的功能基团，热行为和表面形态。 DSC）和扫描电子显微镜（SEM）。结果表明，粘土和氧化锌的共同作用显着提高了纯壳聚糖的机械性能。FTIR结果证实壳聚糖，蒙脱石/金属氧化物的官能团之间具有良好的相容性。当掺入Np-粘土时，Np-ZnO分布在壳聚糖膜中变得更均匀，因此，Np-Clay使Np-ZnO与壳聚糖相容，机械性能得到改善，并且不影响膜的抗菌活性。壳聚糖的热降解温度随​​添加Np-粘土的变化不明显，但随添加Np-ZnO的变化而明显变化。在抗微生物试验中发现，壳聚糖和Np-ZnO具有协同作用 Np-粘土使Np-ZnO与壳聚糖相容，机械性能得到改善，并且不影响薄膜的抗菌活性。壳聚糖的热降解温度随​​添加Np-粘土的变化不明显，但随添加Np-ZnO的变化而明显变化。在抗微生物试验中发现，壳聚糖和Np-ZnO具有协同作用 Np-粘土使Np-ZnO与壳聚糖相容，机械性能得到改善，并且不影响薄膜的抗菌活性。壳聚糖的热降解温度随​​添加Np-粘土的变化不明显，但随添加Np-ZnO的变化而明显变化。在抗微生物试验中发现，壳聚糖和Np-ZnO具有协同作用大肠杆菌和金黄色葡萄球菌。在壳聚糖中添加Np-ZnO和C-Clay可以增强机械性能和抗菌性能，从而使这种材料有望用于食品包装应用。

图形概要