Zou Tao, Kang Lei, Zhang Dongqiao, Li Jieyi, Zheng Zefeng, Peng Xiaohong
School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China.
School of Civil Engineering, Guangzhou University, Guangzhou 510006, China.
Nanomaterials (Basel). 2023 Jul 6;13(13):2018. doi: 10.3390/nano13132018.
The flammability and gas barrier properties are essential for package material. Herein, a highly-oriented self-assembly nanocoating composed of polyvinyl alcohol (PVA) and montmorillonite (MMT) was prepared for endowing polyethylene terephthalate (PET) films with excellent flame retardancy and gas barrier properties. The specific regular nanosheet structure of the PVA/MMT composite nanocoating was confirmed by Fourier transform infrared (FTIR) and X-ray diffraction (XRD). Thermogravimetric analysis (TGA) and the vertical burning test (VBT) suggested that the thermal stability and flame-retardancy of the coated PET films were considerably improved with more pick-up of the resulting nanocoating. When reaching 650 °C, there was still 22.6% char residual left for coated PET film, while only 6% char residual left for pristine PET film. During the vertical burning test, the flame did not spread through the whole PET film with the protection of PVA/MMT nanocoating, and no afterflame was observed. Scanning electron microscopy (SEM) is consistent with vertical burning test, proving that the thermal stability and flame retardancy of coated PET films were considerably enhanced with the increment of PVA/MMT. Thanks to the multi-layer structure, PVA/MMT nanocoating could effectively improve the gas barrier properties of PET films, and the oxygen vapor transmittance rate and water vapor transmittance rate of PET films were more than four hundred times lower and 30% lower than those of neat PET film. Our work demonstrates that bi-functional flame retardant and gas barrier materials could be gained via constructing inorganic/organic highly-oriented self-assembly nanocoating, which is promising in the area of packaging.
易燃性和气体阻隔性能对于包装材料至关重要。在此，制备了一种由聚乙烯醇（PVA）和蒙脱石（MMT）组成的高度取向自组装纳米涂层，以赋予聚对苯二甲酸乙二酯（PET）薄膜优异的阻燃性和气体阻隔性能。通过傅里叶变换红外光谱（FTIR）和X射线衍射（XRD）证实了PVA/MMT复合纳米涂层具有特定规则的纳米片结构。热重分析（TGA）和垂直燃烧试验（VBT）表明，随着所得纳米涂层附着量的增加，涂覆PET薄膜的热稳定性和阻燃性得到显著提高。当温度达到650℃时，涂覆PET薄膜仍有22.6%的残炭，而原始PET薄膜仅剩余6%的残炭。在垂直燃烧试验中，在PVA/MMT纳米涂层的保护下，火焰未蔓延至整个PET薄膜，且未观察到余焰。扫描电子显微镜（SEM）结果与垂直燃烧试验一致，证明随着PVA/MMT含量的增加，涂覆PET薄膜的热稳定性和阻燃性显著增强。得益于多层结构，PVA/MMT纳米涂层可有效提高PET薄膜的气体阻隔性能，PET薄膜的氧气透过率和水蒸气透过率分别比纯PET薄膜低四百多倍和30%。我们的工作表明，通过构建无机/有机高度取向自组装纳米涂层可获得双功能阻燃和气体阻隔材料，这在包装领域具有广阔前景。
