聚乙烯醇/纳米零价铁复合膜的制备及性能

为了克服脱氧剂小袋包装与食品混装带来的工艺不足和安全问题，采用水热法制备了纳米零价铁（nZVI），并将其与聚乙烯醇（PVA）进行溶液共混，制备了结构及阻氧性能更为优异的聚乙烯醇/纳米零价铁复合膜。利用傅里叶变换红外光谱（FTIR）、X射线衍射（XRD）、热重分析（TG）、差示扫描量热法（DSC）等对膜的结构和性能进行表征。结果表明：复合膜中PVA和nZVI实现了良好复合；加入nZVI后，复合膜的玻璃化温度（Tg）升高、热稳定性降低；随着nZVI含量的增加，复合膜的力学性能先增强后减弱，在nZVI质量分数为2%时，复合膜的抗拉强度和断后伸长率达到最大；复合膜的氧气透过系数随着nZVI含量的增加呈现先减小后增大的趋势，在nVZI质量分数为3%时，复合膜的氧气透过系数最小。在复合膜中，nZVI和PVA的羟基之间能形成一种强的相互作用，改善了复合材料的结构和性能，但nZVI及其表面部分氧化的变价铁催化加速了PVA的热降解。

Preparation and Properties of Polyvinyl Alcohol/Nano-Scale Zero-Valent Iron Composite Films

In order to overcome the process insufficiency and safety problems caused by the mixing of oxygen absorber sachets and food, nano zero-valent iron (nZVI) was prepared by hydrothermal method, and it was blended with polyvinyl alcohol (PVA) solution to prepare PVA/nZVI composite films with better structure and oxygen barrier performance. The structure and properties of the membrane were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TG), and differential scanning calorimetry (DSC). The results showed that PVA and nZVI were well combined in the composite film. After adding nZVI, the glass transition temperature (Tg) of the composite film increased and the thermal stability decreased. With the increase in nZVI content, the mechanical properties of the composite film first enhanced and then weakened, and the tensile strength and elongation at break of the composite film reached the maximum when the nZVI mass fraction was 2%. The oxygen permeability coefficient of the composite membrane decreased first and then increased with the increase in nZVI content, and the oxygen permeability coefficient of the composite membrane was the smallest when the nVZI mass fraction was 3%. In the composite film, a strong interaction could be formed between the hydroxyl groups of nZVI and PVA, which improved the structure and properties of the composite, but the valence iron catalyzed by the partial oxidation of nZVI and its surface accelerated the thermal degradation of PVA.