Sulfonated polyimide copolymers based on 4,4′-diaminostilbene-2,2′-disulfonic acid and 3,5,3′,5′-tetramethylbenzidine with enhanced solubility

• Published in: Polymer bulletin (Berlin, Germany) Germany), 2017-03, Vol.74 (3), p.895-909
• Main Authors: Abu-Orabi, Faten M., Kailani, Mohammed H., Sweileh, Bassam A., Mustafa, Mohammad Y., Al-Hussein, Mahmoud
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Complex Fluids and Microfluidics; Copolymers; Diamines; Fuel cells; Glass substrates; High temperature; Ion exchange; Membranes; Nitrogen; NMR spectroscopy; Organic Chemistry; Original Paper; Physical Chemistry; Polyimide resins; Polymer Sciences; Soft and Granular Matter; Solubility; Temperature; Thermal stability; Thermogravimetric analysis
• ISSN: 0170-0839; 1436-2449
• DOI: 10.1007/s00289-016-1752-x

A new series of six-membered ring sulfonated polyimides with different combinations of two comonomers in the nonsulfonated diamine was prepared by one-step high-temperature polycondensation in m -cresol to improve the solubility of the resulting sulfonated polyimides. They are based on 1,4,5,8-naphthalenetetracarboxylic dianhydride, 4,4′-diaminostilbene-2,2-disulfonic acid sulfonated diamine, and equimolar mixture of 3,5,3′,5′-tetramethylbenzidine (TMB) and 4,4′-oxydianiline, bis(4-aminophenyl)methane, or bis(4-(aminophenoxy)-4-phenyl)isopropylidene nonsulfonated diamines. The introduction of TMB comonomer in the nonsulfonated diamine resulted in a remarkable improvement in the solubility of the resulting polyimides in comparison with the corresponding single-monomer nonsulfonated diamine polyimides. Flexible, transparent, and tough membranes were prepared by solution casting method from the different polyimides. The membranes were characterized with FTIR and 1 H-NMR spectroscopy, differential scanning calorimetry, thermogravimetric analysis, water uptake, and ion-exchange capacity measurements. They exhibit high thermal stability and good correlation between the ion-exchange capacity and water uptake values.