High glass transition of organo-soluble copolyimides derived from a rigid diamine with tert-butyl-substituted triphenylpyridine moiety
A new diamine with a tert-buty-substituted triphenylpyridine unit was synthesized and used in the preparation of polyimides via a one-step polymerization. The polyimides are completely amorphous and exhibit good solubility in organic solvents. As a result of the presence of bulky substituents and rigid triphenylpyridine units, the final polyimide products have high glass transition temperatures (up to 365 °C) and good thermal stability with 10% weight loss temperatures in the range 538–563 °C. Triphenylpyridine units and tert-butyl groups might play a key role in improving the solubility of the polyimides while maintaining high glass transition temperatures and good thermal stability. The polyimide films had good mechanical properties.