結晶性聚亞醯胺合成的先期研究

Abstract

本實驗研究以兩種芳香二酸肝與四種芳香二胺所合成的聚亞醯胺 之結晶性。以X光繞射對所合成的五種聚亞醯胺分析的結果顯示其中兩種 聚亞醯胺經200℃的熱環化處理後具有結晶的現象，且結晶的出現與熱處 理的溫度有關。配合熱差掃描分析(DSC)，我們發現在聚亞醯胺具有最低 的玻璃轉移溫度時，結晶出現的趨勢最大，顯然當熱環化處理使聚亞醯胺 的結構具有最大的撓屈性時，分子愈可能堆排成有序的結構；熱環化處理 也須阻止交聯反應的發生否則結晶的現象將消失。熱重分析(TGA)的結果 也顯示所合成的聚亞醯胺均具有約600℃的高熱裂解溫度，因此在高溫應 用方面亦具有相當的潛力。 In this work we studied the crystallinity of polyimides synthesized by two types of aromatic dianhydrides and four types of aromatic diamines. The x-ray diffraction analysis revealed, two of the five different types of synthesized polyimides cured at 200℃ exhibited crystalline behavior. In combination with the differential scanning calorimeter (DSC) analysis, we found the crystallinity seemed to appear in the temperature range when thermal imidization treatment provided polyimides a low glass transition temperature character. This result indicated the ordered packing structure formed when bonding flexibility in polyimides was increased. In addition, the imidization must prevent the occurrence of cross-linking reactions in polyimide otherwise its crystallinity would smear out. All types of polyimides also possessed relatively high thermal decomposition temperatures around 600℃ so that they also have great potential for high-temperature applications, as revealed by thermogravimetric analysis (TGA).