Preparation and Properties of Novel Aromatic Polyimides from 5,7-Diamino-1,1,4,6-Tetramethylindan and Aromatic Tetracarboxylic Dianhydrides

Abstract

Novel aromatic polyimides containing indan structure units were prepared from 5,7-diamino-1,1,4,6-tetramethylindan and various aromatic tetracarboxylic dianhydrides. The glass transition temperatures (T _g’s) of these polyimides were not observed by differential scanning calorimetry at a temperature lower than 500 °C and the 5% weight loss temperatures (T _d ⁵’s) of them were above 422 and 474 °C in air and nitrogen, respectively. Polyimide prepared from 5,7-diamino-1,1,4,6-tetramethylindan and 2,2-bis(3,4-dicarboxyphenyl)-1,1,1,3,3,3-hexafluoropropane dianhydride was soluble in organic solvents such as tetrahydrofuran, cyclopentanone, chloroform, acetone, ethyl acetate, N-methyl-2-pyrrolidinone and cresol at 20 wt% concentration at ambient temperature. The other resulting polyimides obtained from this diamine possessing an indan structure were also soluble in several organic solvents. These results indicated that polymer properties such as thermal behaviour and solubilities were influenced by the indan structure unit in a repeating structure.