Synthesis of highly soluble and transparent polyimides |
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Authors: | Xiaohua Huang Wei Huang Jinyao Liu Lili Meng Deyue Yan |
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Affiliation: | School of Chemistry and Chemical engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, PR China |
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Abstract: | A novel aromatic diamine, 3,3′‐diisopropyl‐4,4′‐diaminophenyl‐4″‐methyltoluene with a 4‐methylphenyl pendant group and isopropyl side groups, was designed and synthesized in this study. Then it was polymerized with various aromatic dianhydrides including pyromellitic dianhydride, 3,3′,4,4′‐biphenyltetracarboxylic dianhydride, 4,4′‐oxydiphthalic anhydride, 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride and 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride via a one‐pot high temperature polycondensation procedure to produce a series of aromatic polyimides. These polyimides exhibited excellent solubility even in common organic solvents, such as chloroform and tetrahydrofuran. The flexible and tough films can be conveniently obtained by solution casting. The films were nearly colorless and exhibited high optical transparency, with the UV cutoff wavelength in the range 302–365 nm and the wavelength of 80% transparency in the range 385–461 nm. Moreover, they showed low dielectric constants (2.73–3.23 at 1 MHz) and low moisture absorption (0.13%–0.46%). Furthermore, they also possessed good thermal and thermo‐oxidative stability with 10% weight loss temperatures (T10%) in the range 489–507 °C in a nitrogen atmosphere. The glass transition temperatures of all polyimides are in the range 262–308 °C. Copyright © 2012 Society of Chemical Industry |
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Keywords: | aromatic polyimide dielectric constant optical transparency solubility thermal stability |
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