Effect of Sulfonic Groups Concentration on IEC Properties in New Fluorinated Copolyamides

Seven aromatic polyamides and copolyamides were synthesized from two different aromatic diamines: 4,4'-(Hexafluoroisopropylidene)bis(p-phenyleneoxy)dianiline (HFDA) and 2,4-Aminobenzenesulfonic acid (DABS). The synthesis was carried out by polycondensation using isophthaloyl dichloride (1SO). T...

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Bibliographic Details
Published in:Polymers 2019-07, Vol.11 (7), p.1169
Main Authors: Pali-Casanova, Ramón de Jesús, Yam-Cervantes, Marcial Alfredo, Zavala-Loría, José Del Carmen, Loría-Bastarrachea, María Isabel, Aguilar-Vega, Manuel de Jesús, Dzul-López, Luis Alonso, Sámano-Celorio, María Luisa, Crespo-Álvarez, Jorge, García-Villena, Eduardo, Agudo-Toyos, Pablo, Méndez-Martínez, Francisco
Format: Article
Language:English
Subjects:
Aramid fibers
Copolymers
Diamines
Dichlorides
Electrochemical impedance spectroscopy
Elongation
Fuel cells
Ion exchange
Mechanical properties
Mechanical tests
Membranes
Modulus of elasticity
Polyamide resins
Polymers
Proton exchange membrane fuel cells
Protons
Solvents
Sulfonic acid
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Summary:Seven aromatic polyamides and copolyamides were synthesized from two different aromatic diamines: 4,4'-(Hexafluoroisopropylidene)bis(p-phenyleneoxy)dianiline (HFDA) and 2,4-Aminobenzenesulfonic acid (DABS). The synthesis was carried out by polycondensation using isophthaloyl dichloride (1SO). The effect of an increasing molar concentration of the sulfonated groups, from DABS, in the copolymer properties was evaluated. Inherent viscosity tests were carried out to estimate molecular weights. Mechanical tests were carried out under tension, maximum strength ( σ ), Young's modulus ( ), and elongation at break (ε ) to determine their mechanical properties. Tests for water sorption and ion exchange capacity (IEC) were carried out. Proton conductivity was measured using electrochemical impedance spectroscopy (EIS). The results indicate that as the degree of sulfonation increase, the greater the proton conductivity. The results obtained showed conductivity values lower than the commercial membrane Nafion 115 of 0.0065 S cm . The membrane from copolyamide HFDA/DABS/1S0-70/30 with 30 mol DABS obtained the best IEC, with a value of 0.747 mmol g that resulted in a conductivity of 2.7018 × 10 S cm , lower than the data reported for the commercial membrane Nafion 115. According to the results obtained, we can suggest that further developments increasing IEC will render membranes based on aromatic polyamides that are suitable for their use in PEM fuel cells.
ISSN:2073-4360
2073-4360
DOI:10.3390/polym11071169