聚乙烯醇/黏土奈米複合材料之合成與物性

Abstract

本研究乃聚乙烯醇/黏土奈米複合材料之混成並分析其性質。使用的黏土為蒙特納石（Na+-Montmorillonite），由於黏土在水中具有高膨潤性，水溶性聚乙烯醇分子鏈進入黏土層與層之間可形成聚乙烯醇/黏土複合材料，利用X-ray鑑定的方法檢驗其是否為奈米複合材料。並選擇兩種不同分子量之聚乙烯醇高分子與黏土形成複合材料，並探討分子量對複合材料物性的影響。 黏土的添加會使得聚乙烯醇的熱膨脹性降低，高溫降低的比低溫大且分子量高者降低也比分子量低之聚乙烯醇為多。在結晶度方面來說，黏土添加的愈多聚乙烯醇高分子結晶性降低的愈多。機械性質方面則有良好的提升，添加10phr的黏土可提升四倍的楊氏模數，分子量高提升的數值則愈大。

Poly(vinyl alcohol) / clay nanocomposites have been synthesized, and their physical properties were investigated. Na+-montmorillonite was first swelled by distilled water and then different amounts of Na+-montmorillonite in water were mixed with poly(vinyl alcohol)(PVA). The solution blends of montmorillonite and PVA were cast into films. The composites were confirmed to be nanocomposites by X-ray diffraction. The in-plane thermal expansion of poly(vinyl alcohol) / clay nanocomposites was reduced by 10% as compared to that of pure poly(vinyl alcohol) at 60℃. The degree of the reduction of thermal expansion at higher temperature for PVA / montmorillonite was greater than that at lower temperature. The degree of crystallinity of 10 phr (100/10) poly(vinyl alcohol) / clay nanocomposites was also reduced by 40% and 56% respectively for M.W. of 22,000 and M.W. of 124,000. The Young's modulus of 10 phr poly(vinyl alcohol) / clay nanocomposites was four times higher than that of pure poly(vinyl alcohol).