Department of Grain Science and Industry, Kansas State University, 201 Shellenberger Hall, Manhattan, Kansas 66506, United States.
J Agric Food Chem. 2011 Dec 14;59(23):12384-95. doi: 10.1021/jf201119v. Epub 2011 Nov 8.
Nanocomposites of starch, poly vinyl alcohol (PVOH), and sodium montmorillonite (Na(+)MMT) were produced by solution mixing and cast into films. Tensile strength (TS) and elongation at the break (E%) of the films ranged from 11.60 to 22.35 MPa and 28.93-211.40%, respectively, while water vapor permeability (WVP) ranged from 0.718 to 1.430 g·mm/kPa·h·m(2). In general, an increase in Na(+)MMT content (0-20%) enhanced TS and decreased E% and WVP. Use of higher molecular weight PVOH increased both TS and E% and also decreased WVP. Mechanical properties were negatively affected, but water vapor barrier properties improved with increasing starch content (0-80%). X-ray diffraction and transmission electron microscopy were used to analyze the nanostructure, and molecular conformations and interactions in the multicomponent nanocomposites were inferred from glass transition behavior. Interactions between starch and PVOH were strongest, followed by polymer/clay interactions. On the basis of this insight, a conceptual model was presented to explain the phenomena of intercalation and exfoliation in the starch/PVOH/Na(+)MMT nanocomposites.
通过溶液混合并浇铸成薄膜的方法制备了淀粉、聚乙烯醇（PVOH）和钠基蒙脱石（Na(+)MMT）的纳米复合材料。薄膜的拉伸强度（TS）和断裂伸长率（E%）分别在 11.60 至 22.35 MPa 和 28.93-211.40%之间变化，而水蒸气透过率（WVP）在 0.718 至 1.430 g·mm/kPa·h·m(2)之间变化。一般来说，Na(+)MMT 含量（0-20%）的增加会提高 TS，降低 E%和 WVP。使用更高分子量的 PVOH 会提高 TS 和 E%，同时降低 WVP。随着淀粉含量（0-80%）的增加，力学性能受到负面影响，但水蒸气阻隔性能得到改善。使用 X 射线衍射和透射电子显微镜分析了纳米结构，并从玻璃化转变行为推断出多组分纳米复合材料中的分子构象和相互作用。淀粉和 PVOH 之间的相互作用最强，其次是聚合物/粘土相互作用。基于这一认识，提出了一个概念模型来解释淀粉/PVOH/Na(+)MMT 纳米复合材料中插层和剥离的现象。
