Synthesis and properties of novel polyimides based on 2',7'-bis(4-aminophenoxy)-spiro(4,5-diazafluorene-9,9'-xanthene)

Abstract

A new class of polyimides had been synthesized from a novel aromatic diamine, 2',7'-bis(4-aminophenoxy)-spiro(4,5-diazafluoren-9,9'-xanthene). Polyimides were prepared by two-stage polycondensation of diamine monomer with various aromatic dianhydride. These polymers showed good thermal stability, solubility and optical transparency. These polymers showed good thermal stability, solubility and optical transparency. Except 6a, all polyimides were dissolved in aprotic polar solvents at room temperature. The glass transition temperatures (T_g) of the poly(ether imide)s were determined to be 338–423 °C and 345–428 °C by dynamic mechanical thermal analyses (DMA) and differential scanning calorimeter (DSC), respectively. Decomposition temperature for 10% weight loss all of these poly(ether imide)s above 560 °C in both nitrogen and air atmospheres. Normalized transparencies in the visible region (400–780 nm) were recorded between 67% and 83%. The dielectric constants of polyimide film were recorded in the range of 2.56–3.12 at 1 KHz.

Graphical Abstract

Keywords:

• 2',7'-bis(4-aminophenoxy)-spiro(4,5-diazafluoren-9,9'-xanthene)
• 4,5-diazafluorene
• thermal stability
• organic soluble
• polyimide

Additional information

Funding

This work was financially supported by the National Natural Science Foundation of China (No. 21908169 and 21606005), Natural Science Foundation of Beijing Municipality (No. 2192016) and the Beijing Key Laboratory of Quality Evaluation Technology for Hygiene and Safety of Plastics (No. PQETGP2020007). This work was also supported by State Key Lab High-Performance Civil Engn Mat (No. 2020CEM007).