SYNTHESIS AND PROPERTIES OF AROMATIC POLYMERS BEARING TRIPHENYLAMINE UNITS

• Main Authors: Chien-Wei Chen, 陳建瑋
• Other Authors: Sheng-Huei Hsiao, Chin-Ping Yang, Wen-Jeng Guo, Guey-Sheng Liou
• Format: Others
• Language: en_US
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/30915307624070061745

碩士 === 大同大學 === 化學工程學系(所) === 92 === ABSTRACT This thesis consists of three parts. The first part deals with the syntheses and properties of novel aromatic polyamides bearing pendent diphenylamino or carbazolyl groups. Two new diamines, 2,4- diaminotriphenylamine and N-(2,4-diaminophenyl)carbazole, were synthesized via the cesium fluoride-mediated aromatic substitution reactions of 1-fluoro-2,4-dinitrobenzene with diphenylamine and carbazole, followed by palladium-on-charcoal-catalyzed hydrazine reduction. Amorphous and soluble polyamides having pendent diphenylamino and carbazolyl groups were prepared by the phosphorylation polycondensation of aromatic dicarboxylic acids with the prepared diamines. Basic properties of these polyamides, such as inherent viscosity, molecular weights, film-forming ability, mechanical properties, crystallinity, solubility, and thermal properties, are investigated and compared with those of parent polyamides derived from m-phenylenediamine and the same aromatic diacids. The second part of this theses describes the synthesis and properties of novel poly(amide-imide)s having pendent diphenylamino groups. A new dicarboxylic acid, 2,4-bis(N-trimellitoyl)triphenylamine, bearing two preformed imide rings was synthesized from the condensation of 2,4-diaminotriphenylamine and trimellitic anhydride at 1 : 2 molar ratio. Two series of poly(amide imide)s with inherent viscosities of 0.38-0.66 dL/g were prepared by triphenylphosphite-activated polycondensation from the diamine monomer with various monoimide- and diimide-dicarboxylic acids or from 2,4-bis(N-trimellitoyl)triphenylamine with various aromatic diamines. All of the poly(amide imide)s were readily soluble in a variety of organic solvents and formed strong and tough films via solution casting. The wholly aromatic poly(amide imide)s have useful levels of thermal stability associated with moderately high glass transtion temperatures (238-314 ℃) and 10 % weight loss temperatures in excess of 490 ℃ in nitrogen or in air. The third part of this thesis investigates the synthesis and properties of novel fluorinated polyimides on the basis of 4,4’-diamino-3”,5”- bis(trifluoromethyl)triphenylamine. A new trifluoromethyl-substituted monomer, 4,4’-diamino-3”,5”-bis(trifluoromethyl)triphenylamine, was prepared via the CsF-mediated aromatic substitution reactions of 3,5-bis(trifluoromethyl)aniline with p-fluoronitrobenzene, followed by Pd-C/hydrazine catalytic reduction. Novel polyimides were synthesized with the diamine and various commercially available aromatic dianhydrides by thermal or chemical imidization routes. All the polyimides could afford transparent, flexible, and strong films with favorable solubility, excellent tensile properties and reasonable dielectric constants of 3.46-3.86 at 10 kHz. These polyimides exhibited appreciate UV-Vis absorption bands at 311–318 nm in NMP solution. The photoluminescence spectra showed maximum bands around 522–562 nm. The softening temperatures of the polyimides were in the range 266-311 ℃, and the 10 % weight-loss temperatures were higher than 550 oC. For a comparative study, a series of analogous polyimides based on 4,4’-diaminotriphenylamine were also prepared and characterized.