Fluorene‐ring‐containing diamine and resultant soluble thermally stable polyamides

A new fluorene‐ring‐containing diamine, N′‐[7‐(acetyl‐4‐aminoanilino)‐9,9‐dioctylflouren‐2‐yl]‐N′‐4‐aminophenyl)acetamide, was prepared through the reaction of 2,7‐dibromo‐9,9‐dioctylfluorene with 4‐aminoacetanilide in the presence of 10 mol % CuI, 20 mol % N,N′‐dimethyl ethylene diamine as a catalyst, and K2CO3 as a base. A series of novel polyamides were prepared by the direct polycondensation of the new diamine with various commercially available aliphatic and aromatic dicarboxylic acids. The novel diamine and the obtained polyamides were characterized with conventional methods (Fourier transform infrared and NMR spectroscopy) and elemental analysis. All the synthesized polyamides showed good solubility in various solvents such as dimethyl sulfoxide, N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethylformamide, hexamethylene phosphoramide, and pyridine and exhibited inherent viscosities in the range of 0.44–0.55 dL/g. According to the differential scanning calorimetry analysis, the glass‐transition temperatures of the polyamides were in the range of 85–196°C. Thermogravimetric analysis of the polyamides indicated a 10% weight loss in the temperature range of 344–417°C in an N2 atmosphere.