초록 |
Wholly alicyclic polyimides (APIs) are promising because of their high optical transparency, high solubility and low dielectric constant. In order for the polyimides to have the desirable properties, they need to have high molecular weight. However, in the preparation of polyimides based on aliphatic diamines, high-molecular-weight polyimides can’t be obtained. This is attributable to the formation of carboxylic acid salt that is due to high basicity of aliphatic amines. In this study, we have compared four synthetic methods of fully APIs, conventional 2-step, N-silylation, in-situ silylation and synthesis using m-cresol. Structures of the APIs were confirmed by 1H NMR and FT-IR spectra. Morphology of the APIs were studied by WAXD. Viscosity of the APIs was measured to compare their molecular weight. Solubility of the APIs was tested in various solvents and thermal property of the APIs was investigated by DSC and TGA. |