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The aromatic diamine 2- (4-aminophenyl) ethylamine (4APEA) is a potential monomer for polymers and advanced materials. Here, 4APEA was produced by fermentation using genetically engineered Escherichia coli (Masuo et al. 2016). Optimizing fed-batch cultures of this strain produced the highest reported yield to date of 4APEA (7.2%; 3.5 g/L versus glucose) within 72 h. Appropriate aeration was important to maximize production and avoid unfavorable 4APEA degradation. Fermented 4APEA was purified from culture medium and polymerized with methylene diphenyldiisocyanate and hexamethylene diisocyanate to produce polyureas PU-1 and PU-2, respectively. The decomposition temperatures for 10% weight loss (T d10) of PU-1 and PU-2 were 276 °C and 302 °C, respectively, and were comparable with that of other thermostable aromatic polyureas. This study is the first to synthesize polyureas from the microbial aromatic diamine. Their excellent thermostability will be useful for the industrial production of heat-resistant polymer materials. [ABSTRACT FROM AUTHOR]

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Novel polyimide with better thermostability, lower dielectric constant and constant loss were synthesized by fluorinated modification and molecular structural design and predicted as coatings with highly electromagnetic wave permeability. 4-(4-aminophenoxy)-3-fluoroaniline (APFA) was obtained by 2-fluoro-4- nitrophenol and 4-nitrochlorobenzene, then the formed 2-fluoro-4-nitro-l-(4-nitrophenoxy) benzene ( FNNB) was transferred by catalytic reduction with hydrazine hydrate and catalyst of Pd/C. The asymmetric fluorinated was synthesized with 6 FDA in DM Ac solution by imidization of polyamic acid. Asymmetric polyimide exhibited excellent thermal stability with the decomposition temperature and the glass transition temperature of 502. 50 and 251. 60 °C . The residual weight (Rw) at 700 t was 49. 86% . AFM images of polyimide film showed that the grain sizes were in narrow ranges with evenly surface and mean roughness of 9. 024 nm. The UV-Vis absorption edge was at 357 nm and the transparency at 450 nm was higher than 80% . The dielectric constant was 3. 65 at 1 MHz and 2. 38 at 10 MHz, and the maximum dielectric loss was 0. 010 7. [ABSTRACT FROM AUTHOR]