Polyimides containing a novel bisbenzoxazole with high Tg and low CTE

A novel diamine named (2,2 '-bibenzoxazole)-5,5 '-diamine (DBOA) and derived polyimides (PIs) were successfully synthesized. The rigid, linear, symmetrical molecular structure and the strong charge transfer complex (CTC) were considered to be the reasons for the improved molecular packing and enhanced thermal properties of the polymers. These DBOA based PIs exhibited a higher glass transition temperature (T-g) and lower coefficient of thermal expansion (CTE) than traditional benzoxazole (BOA) based PIs. Meanwhile, the PI derived from DBOA and BPDA (3,3 ',4,4 '-biphenyltetracarboxylic dianhydride) exhibited high T-g (395 degrees C) and low CTE (8.9 ppm per degrees C), and is expected to be applied in organic light-emitting diode (OLED) displays.

Automated summary

The novel diamine DBOA and its derived polyimides exhibit enhanced thermal properties and improved molecular packing, making them ideal for applications in OLED displays due to their high glass transition temperature and low coefficient of thermal expansion.