A novel non-coplanar aromatic diamine monomer

3

3′-ditertbutyl-4

4′-diaminodiphenyl-4″-naphthylmethane (TAPN) was synthesized by a condensation reaction of 2-tertbutylaniline and 1-naphthaldehyde under catalyst hydrochloric acid. The structure of the monomer was confirmed by FTIR

NMR

elementary analysis and mass spectrometry. A series of aromatic polyimides (PIs) were synthesized

via

conventional one-step polycondensation from TAPN and various commercial aromatic dianhydrides. All of the PIs exhibit excellent solubility in common organic solvents

even in low boiling point solvents such as chloroform (CHCl

3

)

tetrahydrofuran (THF) and acetone. The PIs present outstanding thermal stability with the glass transition temperature (

T

g

) ranged from 299 °C to 350 °C

and the temperature at 10% weight loss ranged from 490 °C to 504 °C

and high optical transparency with the cutoff wavelengths of 306-356 nm. Moreover

the flexible and tough PI films have prominent mechanical properties with tensile strengths in the range of 77.6-90.5 MPa

tensile modulus in the range of 1.8-2.4 GPa and elongation at break in the range of 6.3%-9.5%

as well as lower dielectric constant (2.89-3.12 at 1 MHz) and lower moisture absorption (0.35%-0.66%).