Preparation and properties of polyimide films derived from hexaazatriphenylenehexacarboxylic acid trianhydride

In this study, a new polyimide film were prepared using monomers with different proportions of hexaazatriphenylene-ternary-anhydride (HAT-T). This material had higher molecular weights (Mn =1.81–11.4 × 106; Mw=2.32–15.5 × 106) and narrow molecular weight distribution (PDI=1.10–1.36). With the introduction of HAT-T, the glass transition temperature (Tg) of the polyimide film exceeded 300 °C, and the temperature for 5% decomposition in N2 exceeded 520 °C. The polyimide exhibited good mechanical properties (TS = 63.39–77.81 MPa; EB = 4.50~7.72%). The polyimide film with HAT-T had a micro-crosslinked structure, and its coefficient of thermal expansion decreased by 97 ppm/K. This work has potential contributions to the study of flexible display substrate materials.