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

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1169 ◽  
Author(s):  
Ramón Pali-Casanova ◽  
Marcial Yam-Cervantes ◽  
José Zavala-Loría. ◽  
María Loría-Bastarrachea ◽  
Manuel Aguilar-Vega ◽  
...  

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 max), Young’s modulus (E), and elongation at break (εmax) 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−1. 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−1 that resulted in a conductivity of 2.7018 × 10−4 S cm−1, 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.

2017 ◽  
Vol 30 (4) ◽  
pp. 437-445 ◽  
Author(s):  
Wadi Elim Sosa-González ◽  
Ramón del Jesús Palí-Casanova ◽  
Yamile Pérez-Padilla ◽  
María Isabel Loría-Bastarrachea ◽  
José Luis Santiago-García ◽  
...  

Several aromatic sulfonated copoly(ether–amide)s, based on the aromatic diamines 4,4′-(hexafluoroisopropylidene)bis(p-phenyleneoxy)-dianiline (HFD) and 2,4-diaminobenzensulfonic acid (DABS) and 4,4′-oxybis(benzoic acid) (OBA), were synthesized through a polycondensation reaction. The sulfonation degree was controlled by introducing different concentrations of 2,4-DABS from 40 mol% up to 80 mol%. Proton nuclear magnetic resonance validated the expected concentrations of sulfonic acid groups in the sulfonated aromatic copoly(ether–amide)s. Thermal decomposition of sulfonic groups was found to initiate at 280°C, while main chain decomposition initiates at 410°C. Proton conductivity between 30°C and 75°C was 19.0 and 45.0 mS/cm, respectively, for the copolymer with the highest concentration of sulfonic groups (–SO3H). Comparison with structurally similar sulfonated copolyamides and copoly(ether–amide)s indicates that these new sulfonated copoly(ether–amide)s based on 4,4′-OBA show improved mechanical properties, but a decrease in ion exchange capacity and proton conductivity.


Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 130
Author(s):  
Carlos Corona-García ◽  
Alejandro Onchi ◽  
Arlette A. Santiago ◽  
Araceli Martínez ◽  
Daniella Esperanza Pacheco-Catalán ◽  
...  

The future availability of synthetic polymers is compromised due to the continuous depletion of fossil reserves; thus, the quest for sustainable and eco-friendly specialty polymers is of the utmost importance to ensure our lifestyle. In this regard, this study reports on the use of oleic acid as a renewable source to develop new ionomers intended for proton exchange membranes. Firstly, the cross-metathesis of oleic acid was conducted to yield a renewable and unsaturated long-chain aliphatic dicarboxylic acid, which was further subjected to polycondensation reactions with two aromatic diamines, 4,4′-(hexafluoroisopropylidene)bis(p-phenyleneoxy)dianiline and 4,4′-diamino-2,2′-stilbenedisulfonic acid, as comonomers for the synthesis of a series of partially renewable aromatic-aliphatic polyamides with an increasing degree of sulfonation (DS). The polymer chemical structures were confirmed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (1H, 13C, and 19F NMR) spectroscopy, which revealed that the DS was effectively tailored by adjusting the feed molar ratio of the diamines. Next, we performed a study involving the ion exchange capacity, the water uptake, and the proton conductivity in membranes prepared from these partially renewable long-chain polyamides, along with a thorough characterization of the thermomechanical and physical properties. The highest value of the proton conductivity determined by electrochemical impedance spectroscopy (EIS) was found to be 1.55 mS cm−1 at 30 °C after activation of the polymer membrane.


2006 ◽  
Vol 4 (1) ◽  
pp. 56-64 ◽  
Author(s):  
Tetsuya Yamaki ◽  
Junichi Tsukada ◽  
Masaharu Asano ◽  
Ryoichi Katakai ◽  
Masaru Yoshida

We prepared novel ion exchange membranes for possible use in polymer electrolyte fuel cells (PEFCs) by the radiation-induced graft copolymerization of styrene and new crosslinker bis(vinyl phenyl)ethane (BVPE) into crosslinked polytetrafluoroethylene (cPTFE) films and subsequent sulfonation and then investigated their water uptake, proton conductivity, and stability in an oxidizing environment. In contrast to the conventional crosslinker, divinylbenzene (DVB), the degree of grafting of styrene∕BVPE increased in spite of high crosslinker concentrations in the reacting solution (up to 70mol%). Quantitative sulfonation of the aromatic rings in the crosslinked graft chains resulted in the preparation of membranes with a high ion exchange capacity that reached 2.9meq∕g. The bulk properties of the membranes were found to exceed those of Nafion membranes except for chemical stability. The emphasis was on the fact that the BVPE-crosslinked membranes exhibited the higher stability in the H2O2 solution at 60°C compared to the noncrosslinked and DVB-crosslinked ones, as well as decreased water uptake and reasonable proton conductivity. These results are rationalized by considering the reactivity between styrene and the crosslinker, which is an important factor determining the distribution of the crosslinks in the graft component. In the case of BVPE, the crosslinks at a high density were homogeneously incorporated even into the interior of the membrane because of its compatibility with styrene while the far too reactive DVB led to a crosslink formation only near the surface. The combination of both the cPTFE main chain and BVPE-based grafts, i.e., a perfect “double” crosslinking structure, is likely to effectively improve the membrane performances for PEFC applications.


Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6050
Author(s):  
Khurram Liaqat ◽  
Srosh Fazil ◽  
Wajid Rehman ◽  
Shaukat Saeed ◽  
Farid Menaa ◽  
...  

For improving the hydrolytic stability of sulfonated polyimides consisting of five membered anhydrides, novel sulfonated polyimides (NSPIs) were prepared via polymerization of 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA), with a novel diamine monomer with a pendant sulfonic acid group and 4,4-oxydianiline. Water uptake of this NSPI with an excellent film-forming ability was almost equal to that of Nafion® 117, while their ion exchange capacity (IEC) was 22% higher than Nafion® 117. The loss in weight decreased by 53% and loss in IEC decreased by 66% compared to that of Nafion® 117; both were used to quantitatively measure hydrolytic stability, and radical oxidative stability also increased by 75% when compared with Nafion® 117. Mechanically, this NSPI was superior, and its proton conductivity was higher than Nafion® 117 at elevated temperatures. All these improvements were due to the introduction of this pendant group. Taken together, we herein report a promising renewable energy source based on SPIs capable of displaying proton conductivity and enhanced hydrophilicity.


2021 ◽  
Vol 21 (3) ◽  
pp. 1845-1853
Author(s):  
Lei Jin ◽  
Md Mahabubur Rahman ◽  
Faiz Ahmed ◽  
Taewook Ryu ◽  
Sujin Yoon ◽  
...  

Thermally and chemically stable, sulfonyl imide-based polymer blends have been prepared from sulfonimide poly(arylene ether sulfone) (SI-PAES) and sulfonimide Parmax-1200 (SI-Parmax-1200) using the solvent casting method. Initially, sulfonimide poly(arylene ether sulfone) (SI-PAES) polymers have typically been synthesized via direct polymerization of bis(4-chlorophenyl) sulfonyl imide (SI-DCDPS) and bis(4-fluorophenyl) sulfone (DFDPS) with bisphenol A (BPA). Subsequently, SI-Parmax-1200 has been synthesized via post-modification of the existing Parmax-1200 polymer followed by sulfonation and imidization. The SI-PAES/SI-Parmax-1200 blend membranes show high ion exchange capacity ranging from 1.65 to 1.97 meq/g, water uptake ranging from 22.8 to 65.4% and proton conductivity from 25.9 to 78.5 mS/cm. Markedly, the SI-PAES-40/SI-Parmax-1200 membrane (blended-40) exhibits the highest proton conductivity (78.5 mS/cm), which is almost similar to Nafion 117® (84.73 mS/cm). The thermogravimetric analysis (TGA) and Fenton's test confirm the excellent thermal and chemical stability of the synthetic polymer blends. Furthermore, the scanning electron microscopy (SEM) study shows a distinct phase separation at the hydrophobic/hydrophilic segments, which facilitate proton conduction throughout the ionic channel of the blend polymers. Therefore, the synthetic polymer blends represent an alternative to Nafion 117® as proton exchangers for fuel cells.


2018 ◽  
Vol 18 (2) ◽  
pp. 313 ◽  
Author(s):  
Muhammad Ridwan Septiawan ◽  
Dian Permana ◽  
Sitti Hadijah Sabarwati ◽  
La Ode Ahmad ◽  
La Ode Ahmad Nur Ramadhan

Chitosan was modified by maleic anhydride, and it was then functionalized using heterogeneous and blending method to obtain the membrane. The results of the reaction between chitosan with maleic anhydride were signed by the new peak appears around 1475 cm-1 which attributed to C=C bending of alkene. The new peak also appears at 1590 cm-1 which attributed to N-H bending of amide. Chitosan-maleic anhydride membranes show microstructure of chitosan membrane with high porous density and rigidity while chitosan-maleic anhydride membranes have clusters. In addition, the thermal tenacity of membranes reached 500 °C. Modified membrane by heterogeneous and blending method have higher water uptake, ion exchange capacity, and proton conductivity than chitosan membrane. Moreover, the blending method is much more effective than the heterogeneous method that can be exhibited from ion exchange capacity and proton conductivity values of 1.08–6.38 meq g-1 and 1x10-3–1x10-2 S cm-1, 0.92–2.27 meq g-1 and 1.53x10-4–3.04x10-3 S cm-1, respectively. The results imply that modification of chitosan membrane with the addition of maleic anhydride using heterogeneous and blending method can be applied to proton exchange membrane.


Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 395
Author(s):  
Jonathan Teik Ean Goh ◽  
Ainul Rasyidah Abdul Rahim ◽  
Mohd Shahbudin Masdar ◽  
Loh Kee Shyuan

The polymer electrolyte membrane (PEM) is a key component in the PEM fuel cell (PEMFC) system. This study highlights the latest development of PEM technology by combining Nafion® and ionic liquids, namely 2–Hydroxyethylammonium Formate (2–HEAF) and Propylammonium Nitrate (PAN). Test membranes were prepared using the casting technique. The impact of functional groups in grafting, morphology, thermal stability, ion exchange capacity, water absorption, swelling and proton conductivity for the prepared membranes is discussed. Both hybrid membranes showed higher values in ion exchange capacity, water uptake and swelling rate as compared to the recast pure Nafion® membrane. The results also show that the proton conductivity of Nafion®/2–HEAF and Nafion®/PAN membranes increased with increasing ionic liquid concentrations. The maximum values of proton conductivity for Nafion®/2–HEAF and Nafion®/PAN membranes were 2.87 and 4.55 mScm−1, respectively, equivalent to 2.2 and 3.5 times that of the pure recast Nafion® membrane.


2020 ◽  
Vol 16 ◽  
Author(s):  
Mohd Imran Ahamed ◽  
Nimra Shakeel ◽  
Naushad Anwar ◽  
Lutfullah ◽  
Anish Khan

: In this work, we demonstrate the synthesis of Kraton ionomer membrane by solution casting method. Kraton ionomer membrane was coated with polyaniline by in situ oxidative chemical polymerization to get electrical conductance in the membrane. The synthesized composite membrane of Kraton/polyaniline ionomer further characterized by electrochemical studies to check the redox properties of the material. Similarly, the ion exchange capacity and proton conductivity and selectivity of the synthesized membrane was also determined. From the selectivity studies which shows that the membrane was selective for Cu (II) ions. Furthermore, the outcomes of the membrane such as high ion exchange capacity, good proton conductivity, and efficient selectivity, displays the synthesized membrane is efficient for the preparation of ion-selective membrane electrode. The minimum concentration range of Cu (II) ions towards the ion-selective membrane was 1 × 10-1 to 1 × 10-8 M. The electrode revealed a Nernstian slope of 28.15 mV/decade change in concentration of Cu (II) ions. In addition, the electrode exposed fast response time of 10s, working pH range of 3-6.5, detection limit of 1 × 10-9 M and appreciably good selectivity towards Cu (II) ions over alkali, alkaline, and other heavy metal ions. Moreover, it can be employed as indicator electrode for the potentiometric titration of Cu (II) ions by using ethylene diamine tetraacetic acid, disodium salt (EDTA).


In this study the cation exchange membranes(CEM) were fabricated using 3 different compositions of sulphonated poly vinyl alcohol (SPVA) and phosphorylated graphene oxide(PGO) in weight ratios by physicalmixing and casting method. Loading of PGO in the SPVA improvedwater uptake property which signifies increase in ion exchange capacity(IEC) and proton conductivity as presence of acidic groups were characterized. These fabricated membranes performances were assessed in microbial fuel cells(MFCs) and characterized using XRD and FTIR for its compositional analysis. Due to proper proton conducting channelsmost suitable CEM (SPVA-PGO-3) revealed higher proton conductivity 9.0 x 10-2 S/cm at 27oC, water uptake 114%, area swelling 54.2% and ion exchange capacity (IEC) 1.92 meq/g. The power density obtained for this composite membrane applied in MFC-3 was observed to be 503.1 mW/m2 while the COD removal results obtained as 80.8 %.


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