Synthesis and characterization of a novel organo-soluble polyimide containing hydroxyl and bis-tert-butyl substituted triphenylpyridine units

A new diamine containing hydroxyl and bis-tert-butyl substituted triphenylpyridine units was synthesized and used in the synthesis of polyimides (PIs) via a one-step polymerization. The diamine and PIs were characterized by FTIR and 1H-NMR. The aggregated structure of PIs was amorphous by wide angle X-ray diffraction test and all of them exhibited excellent solubility in most organic solvents. The bis-tert-butyl and triphenylpyridine units endowed PIs excellent thermal stability with 10% weight loss temperatures in the range 493–525 °C and high glass transition temperature in the range 301–344 °C, while the existence of hydroxyl groups provided the possibility for further modification of polymer. The PI membranes had excellent mechanical properties with tensile strength in the range 65–93 MPa. The density of PIs was lower with density in the range 1.266–1.289 g/cm3. It was foreseeable that PIs will greatly promote the applications of heat-resistant and lightweight PI materials in the future.