1313406-75-5Relevant academic research and scientific papers
Synthesis and characterization of triptycene-based polyimides with tunable high fractional free volume for gas separation membranes
Wiegand, Jennifer R.,Smith, Zachary P.,Liu, Qiang,Patterson, Christopher T.,Freeman, Benny D.,Guo, Ruilan
, p. 13309 - 13320 (2014/08/18)
Robust polymer membranes that are highly permeable and selective are desired for energy efficient gas separation processes. In this study, a series of rigid, bulky triptycene-based diamine monomers were designed, synthesized, and subsequently incorporated into the backbone of polyimides via polycondensation with 2,2′-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) to obtain a series of polyimide membranes with high fractional free volume. These triptycene-containing polyimides with systematic variations in their chemical structure demonstrate the viability of the 'tunable' fractional free volume by introducing various substituents onto the polymer backbone. All the polyimides synthesized exhibited film-forming high molecular weight, high solubility, and excellent thermal properties, with glass transition temperatures ranging from 280 °C to 300 °C and thermal stability up to 500 °C. Compared to other classes of glassy polymers, these triptycene-polyimides had high combinations of permeability and selectivity, suggesting that a favorable free volume size distribution in these triptycene polyimides was induced by the unique chain packing mechanism of triptycene units. The correlation between gas transport properties and the polymer chemical structure was also investigated. Altering the size of the substituents neighboring the triptycene units provides greater opportunity to fine-tune the fractional free volume and free volume size distribution in the polymer, which in turn can change the transport properties effectively to meet various separation needs. It is expected that additional design modifications made by exploiting the chemistry versatility of the triptycene moiety and by selectively adding other components may improve these membranes to break the gas permeability-selectivity trade-off barrier. This journal is the Partner Organisations 2014.
Synthesis and properties of novel triptycene-based polyimides
Hsiao, Sheng-Huei,Wang, Hui-Min,Chen, Wen-Jeng,Lee, Tzong-Ming,Leu, Chyi-Ming
, p. 3109 - 3120 (2012/05/05)
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 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 imidizations. 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 and decreases their dielectric constants. The fluorinated polyimides 9d and 9f derived from diamine 6 with 4,4′-oxydiphthalic anhydride and 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA), respectively, could afford almost colorless thin films.
