new unsymmetrical diamine monomer, 2,4-diaminophenyl [40-(200,600-diphenyl-400-pyridyl)phenyl] ether, was successfully synthesized by nucleophilic substitution of 1-chloro-2,4-dinitrobenzene with 4-(20,60-diphenyl- 40-pyridyl) phenol. The diamine monomer was characterized by FTIR, 1H and 13C NMR, and elemental analysis techniques and used for the preparation of novel polyimides (PIs) by reaction with commercially available tetracarboxylic dianhydrides such as pyromellitic dianhydride, 3,30,4,40-benzophenone tetracarboxylic dianhydride, and bicyclo[2.2.2]-oct- 7-ene-2,3,5,6-tetracarboxylic dianhydride. These PIs with inherent viscosities ranged from 0.43 to 0.48 dL/g were readily soluble in many organic solvents and afforded tough and flexible films by solution casting. These polymers exhibited Tgs between 237 and 294C, and 10% weight loss temperatures in excess of 500C with up to 56% char yield at 600C in air. Their maximum fluorescence emission in dilute (0.2 g/dL) NMP solution appeared at 450 nm.
کلید واژگان :polyimide; polycondensation; thermal properties; solubility
ارزش ریالی : 600000 ریال
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