Preparation and Function of Novel Polyimide Derivatives

本项目首次阐明了聚酰亚胺凝胶的制备及其性能。通过(1)聚酰胺酸自发凝胶，(2)添加交联试剂，(3)聚酰亚胺链化学交联制备聚酰亚胺凝胶。异氰酸酯是交联试剂之一，其化学结构直接影响凝胶化反应。在水- nmp混合溶液中观察了聚酰亚胺凝胶的体积相变现象。根据溶剂的不同，体积变化是连续的还是不连续的。其机理涉及到氢键和溶剂介电性的变化。这些现象也被观察到在相变过程中的荧光变化。聚酰亚胺凝胶的荧光效率高于普通聚酰亚胺。聚酰亚胺凝胶的吸光度比常规聚酰亚胺薄膜小，表明它们具有较小的介电常数。这种特性是聚酰亚胺凝胶在高速电子应用中的一大优势。

Preparation and properties of polyimide gels were clarified for the first time under this project. Polymide gels were prepared by (1) spontaneous gelation of polyamide acids, (2) addition of crosslinking reagent, and (3) chemically crosslinking of polyimide chains. Isocianates are one of the crosslinking reagents, whose chemical structure affects on the gelation reactions.Volume phase change phenomena of the polyimide gels were observed in Water-NMP mixed solution. The volume change occurs continuously or discontinuously depending on the solvent. The mechanism involves change of hydrogen bonds and dielectricity of the solvents.Those phenomena were also observed by the fluorescence change during phase transition. Fluorescence efficiency of the polyimide gels was higher than or dinary polyimides. Absorbance of the polyimide gels was smaller than conventional polyimide films, showing that they have small dielectric constants. This properties is one of the great advantage of polyimide gels in applying high speed electronics.