English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/202894
Share/Impact:
Statistics
logo share SHARE logo core CORE   Add this article to your Mendeley library MendeleyBASE

Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar a otros formatos:

Title

Aromatic polyimides and copolyimides containing bulky t-butyltriphenylmethane units

AuthorsCastro-Blanco, R. A.; Rojas-Rodríguez, M.; Hernández, A.; Lozano López, Ángel Emilio ; Alexandrova, L.; Aguilar-Lugo, Carla
KeywordsPolyimides
Soluble polyimides
Diamine triphenylmethane
Gas permeation
Issue Date2019
PublisherSpringer
CitationPolymer Bulletin (2019)
AbstractTriphenylmethane-based polyimides and copolyimides containing bulky t-butyl group (tBu) were obtained by one-step high temperature polycondensation of 2,2′-bis-(3,4-dicarboxyphenyl) hexafluoropropane dianhydride with diamines of triphenylmethane (TPM) family. The polymers were obtained in quantitative yields with inherent viscosities of 0.45–0.80 dL/g. They exhibited high thermal stability with 5% weight loss above 500 °C and were cast in films with good mechanical properties capable of testing as gas separation membranes. All polyimides were readily soluble in polar aprotic solvents, and the solubility enhanced with the increase in tBu-group content. The amorphous, free-standing membranes were prepared from these polymers, and their permeabilities and selectivities to several gases were measured and discussed with respect to the structural differences in the polymers. It was shown that the presence of bulky tBu-units made the chain packing less efficient; free volume and d-spacing in the polyimides grew accordingly. As a consequence, the membranes with higher content of tBu-groups demonstrated improved permeabilities, showing 1.5–3.0 times higher permeability coefficients depending on the gas tested. The membranes’ separation performance was improved for CO/CH gas pair in comparison with that of structurally similar polyimides, while it did not change for O/N pair. Additionally, the mechanism of formation of triphenylmethane diamines in the reaction between aniline and benzaldehydes was investigated in order to optimize the monomer synthesis and to minimize possible side reactions. It was established that the secondary diamines, so-called aminals, were inevitable side products, particularly important in the condensation between aniline and tBu-benzaldehyde.
Publisher version (URL)http://dx.doi.org/10.1007/s00289-019-03003-7
URIhttp://hdl.handle.net/10261/202894
Identifiersdoi: 10.1007/s00289-019-03003-7
issn: 0170-0839
issn: 1436-2449
Appears in Collections:(ICTP) Artículos
Files in This Item:
File Description SizeFormat 
accesoRestringido.pdf15,38 kBAdobe PDFThumbnail
View/Open
Show full item record
Review this work
 

Related articles:


WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.