Synthesis and properties of organosoluble polyimides derived from bis(4‐amino‐3,5‐dimethyl phenyl) halo phenyl methane and various dianhydrides

A series of organosoluble polyimides with various aromatic tetracarboxylic acid dianhydrides was prepared from diamine monomers using one‐ and two‐step methods. All the polyimides were soluble in aprotic solvents such as NMP, DMF, DMAc, and DMSO. The polyimides showed excellent thermal stability and good mechanical properties. The glass‐transition temperature of the prepared polyimides ranged from 210°C to 325°C. All the polyimides formed tough transparent films, with tensile strength of 84–118 MPa, 8%–12% elongation, and 1.5–2.3 GPa modulus. These polyimide films were found to have a dielectric constant in the range of 3.29–3.80 at 1 kHz and 3.14–3.76 at 10 kHz and low moisture uptake, 0.52%–1.10%.