聚亞醯胺與黏土納米複合材料之合成與性質

Abstract

本研究乃合成數種嶄新的聚亞醯胺/黏土納米複合材料及分析其物性。首 先使用12-aminolauric acid , 12-dodecylamine , 1,12-diaminodedcane , 4,4-oxydianoiliane , p-phenylenediamine來 改質黏土，製備得12COOH-MONT , 12CH3-MONT , 12NH2-MONT , ODA-MONT , PPD-MONT等有機黏土。再合成PMDA/ODA , BPDA/ODA , ODPA/ODA 等三 種聚醯胺酸。然後將有機黏土和聚醯胺酸在DMAc溶劑中混合，經加熱脫水 閉環反應後，形成聚亞醯胺/黏土複合材料。利用X-ray繞射分析鑑定是否 為納米複合材料。有機黏土中，使用芳香族夾入劑形成的芳香族有機黏土 在溶劑DMAc的分散性較脂肪族有機黏土來的好，而有機黏土在DMAc的分散 性將影響納米複合材料的形成與否。此外影響聚亞醯胺/黏土納米複合材 料形成的因素尚有：聚亞醯胺的結構、混成物厚度、聚醯胺酸與黏土的混 合時間。因為蒙特納石為矽酸鹽層所堆積而成的其結構為100nm×100nm ×1nm，所以聚亞醯胺/黏土納米複合材料能有效地改善聚亞醯胺的性質。 添加6wt﹪有機黏土所形成的聚亞醯胺/納米複合材料，其垂直於平面之熱 膨脹係數為原來純聚亞醯胺的一半。納米複合材料對於聚亞醯胺的熱穩定 性亦有些許的改進。此外，有機黏土可以降低聚醯胺酸亞醯胺化的反應溫 度。 New types of polyimides-clay composites have been synthesised. Natural Na-montmorillonite was cation exchanged for the ammonium cation of 12-aminolauric acid, 12-dodecylamine, 1,12-dimaninodedcane, 4,4-oxydianoiliane and p-phenylenediamine to form organic clays. Then , PMDA-ODA , BPDA-ODA , ODPA-ODA polyamic acids were synthesized. Organic clays and synthesized polyamic acids in dimethylacetamide were mixed homogenerously, and subsequently casted into films. They were subject to thermal treatment for converting to polyimides-clay composite. Polyimides-clay nanocomposites were confirmed by wide-angle X- ray analysis from the disappearance of the crystal structural of organic clay. It was found that aromatic organic clays（ODA-MONT , PPD-MONT）were dispersed more homogenously than aliphatic organic clays（12COOH-MONT , 12CH3-MONT , 12NH2-MONT） in DMAc solvent. The preparation of polyimides-clay nanocomposites have been influenced by the dispersion of organic clays in DMAc , the structure of polyimides , the thickness of the samples and the mixing time in DMAc.The thermal expansion coefficients in the thickness-direction of the polyimide-clay nanocomposites films were brought down to a half of its original value of the neat polyimide film by the addition of 6wt﹪organic clay. Furthermore , these polyimide-clay nanocomposites had higher thermal stability than that of comesponding polyimides. The imidization temperatures of these polyamic acid - clay solutions were also reduced by the presence of these organic clays.