Shar Abdul Shakoor, Zhang Caili, Song Xieqing, Weng Yunxuan, Du Qiuyue
College of Chemistry and Materials Engineering, Beijing Technology and Business University, Beijing 100048, China.
Fenghua Research Institute of Ningbo University of Technology, Ningbo 315500, China.
Polymers (Basel). 2021 Nov 16;13(22):3962. doi: 10.3390/polym13223962.
Polymer/clay composites are an innovative class of materials. In this study, we present a facile method for the preparation of biodegradable and robust PLA/organomodified montmorillonite (OMMT) composite films with excellent gas barrier performance. When the design of PLA/OMMT composite films, in addition to making OMMT have good intercalation effect in the matrix, the compatibility of intercalating polymer and matrix should also be considered. In this work, two polymers with high gas barrier properties, namely poly(vinyl alcohol) (PVA) and ethylene vinyl alcohol copolymer (EVOH), were selected to intercalate OMMT. The morphology and microstructures of the prepared PLA/PVA/OMMT and PLA/EVOH/OMMT composites were characterized by the X-ray diffraction measurement, scanning electron microscopy, and differential scanning calorimetry. It was shown that the good dispersibility of PVA in the PLA matrix, rather than the intercalation effect, was responsible for the improved gas barrier and mechanical properties of PLA/PVA/OMMT composite. The elongation at break increases from 4.5% to 22.7% when 1 wt % PVA is added to PLA/OMMT. Moreover, gas barrier of PLA/PVA1/OMMT measured as O permeability is 52.8% higher than that of neat PLA. This work provides a route to intercalate OMMT interlayer with high gas barrier polymers and thus can be a useful reference to fabricate PLA/OMMT composites with improved gas barrier and mechanical properties. A comparison of oxygen permeabilities with existing commercial packaging films indicates that the biodegradable PLA/PVA/OMMT may serve as a viable substitute for packaging film applications.
聚合物/粘土复合材料是一类创新性材料。在本研究中，我们提出了一种简便的方法来制备具有优异气体阻隔性能的可生物降解且坚固的聚乳酸/有机改性蒙脱土（OMMT）复合薄膜。在设计聚乳酸/OMMT复合薄膜时，除了要使OMMT在基体中具有良好的插层效果外，还应考虑插层聚合物与基体的相容性。在这项工作中，选择了两种具有高气体阻隔性能的聚合物，即聚乙烯醇（PVA）和乙烯-乙烯醇共聚物（EVOH）来插层OMMT。通过X射线衍射测量、扫描电子显微镜和差示扫描量热法对制备的聚乳酸/PVA/OMMT和聚乳酸/EVOH/OMMT复合材料的形态和微观结构进行了表征。结果表明，PVA在聚乳酸基体中的良好分散性而非插层效果，是聚乳酸/PVA/OMMT复合材料气体阻隔性能和力学性能提高的原因。当向聚乳酸/OMMT中添加1 wt%的PVA时，断裂伸长率从4.5%增加到22.7%。此外，以氧气透过率衡量的聚乳酸/PVA1/OMMT的气体阻隔性能比纯聚乳酸高52.8%。这项工作提供了一种用高气体阻隔聚合物插层OMMT层间的途径，因此可为制备具有改进气体阻隔性能和力学性能的聚乳酸/OMMT复合材料提供有用的参考。与现有商业包装薄膜的氧气透过率比较表明，可生物降解的聚乳酸/PVA/OMMT可作为包装薄膜应用的可行替代品。
