Synthesis and Properties of Triptycene-containing Polyimides

Autor: Wenjeng Chen, 陳文正
Rok vydání: 2010
Druh dokumentu: 學位論文 ; thesis
Popis: 98
Two new triptycene containing bis(ether amine)s, 1,4-bis(4-aminophenoxy)triptycene (4) and 1,4-bis(4-amino-2-trifluoromethylphenoxy)- triptycene (6), were synthesized respectively from the nucleophilic chloro-displacement reactions of p-chloronitrobenzene and 2-chloro-5-nitrobenzotrifluoride with 1,4-dihydroxytriptycene in the presence of potassium carbonate, followed by palladium-catalyzed hydrazine reduction of the dinitro intermediates. The newly synthesized bis(ether amine)s were polymerized with six commercially available aromatic tetracarboxylic dianhydrides to obtain two series of novel triptycene-based polyimides 8a-f and 9a-f by using a conventional two-step synthetic method via thermal and chemical imidization. All the resulting polyimides exhibited high enough molecular weights to permit the casting of flexible and strong films with good mechanical properties. Incorporation of trifluoromethyl groups in the polyimide backbones improves their solubility without decreasing their physical properties. Most of the polyimides derived from the fluorinated monomer 6, especially those prepared via the chemical imidization method, were soluble in aprotic polar solvents. In general, the trifluoromethyl-substituted 9 series polyimides showed a reduced color intensity, a slightly lowered glass-transition temperature (Tg), and comparable thermal stability as compared to the corresponding 8 series analogs. The fluorinated polyimides 9a-f showed high Tg in the range of 272–335 oC and did not reveal significant decomposition before 500 oC in nitrogen or in air. The fluorinated polyimides 9d and 9f derived from diamine 6 with 4,4’-oxydiphthalic anhydride (ODPA) and 4,4’-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), respectively, could afford almost colorless thin films.
Databáze: Networked Digital Library of Theses & Dissertations
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