Characterization and evaluation of Nafion HP JP as proton exchange membrane: transport properties, nanostructure, morphology, and cell performance

Kamel, M.; Mohamed, Hashim; Abdel-Hamed, M.O.; Abdel-Hady, E.E.

doi:10.1007/s10008-019-04366-7

Cited by 20 publications

(18 citation statements)

References 79 publications

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“…Figure 2A shows the thermal properties of the three membranes (F‐950, F‐1050, and F‐14100). The present results are similar to the data of Kamel et al, 21 where the weight‐loss behavior of all the membranes consists of four regions; 1) From 30 to 310°C region, it is assigned to the removal of free and trapped water molecules and possibly other membrane contaminants 32 . 2) From 310 to 410°C region, where the change in the weight is from the de‐sulfonation process 33 .…”

Section: Resultssupporting

confidence: 90%

“…The measurement was performed at RH of 35%, 25°C, and 0.01 cm/min elongation rate. For all the membranes, the stress–strain curves were analyzed, and Young's modulus was determined using the stress–strain curve's starting slope as, 21

{Young}^{'} normals modulus ((), MPa) goodbreak= \frac{Stress ((), MPa)}{Strain} .

The dynamic mechanical analysis (DMA) technique is utilized to examine the mechanical and viscoelastic properties of the membranes with temperatures (20–260°C). The measurements were performed for as received membranes in the air by tensile mode on a Triton DMA analyzer (Tritec 2000, Shimadzu).…”

Section: Methodsmentioning

confidence: 99%

“…Using a refractometer (2WAJ ABBE), the refractive index of the solution in the chamber B was determined and the methanol concentration was computed. The methanol permeability ( P ) was obtained by looking at the connection between concentration of methanol in the chamber B and the penetration time as, 21

P ((), m^{2} / s) = {mLV}_{B} / {SC}_{A},

where m is the incline of the straight‐line connection between the concentration of methanol in the chamber B and the time of penetration. The volume of the solution in the chamber B is denoted by V B and the methanol concentration in the chamber A is denoted by C A .…”

Section: Methodsmentioning

confidence: 99%

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Humidity effect on the transport properties of per‐fluorinated sulfonic acid/PTFE proton exchange membranes: Positron annihilation study

El-Sharkawy

Mohamed

Hassanien

et al. 2021

Polymers for Advanced Techs

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The positron annihilation lifetime (PAL) technique was used to investigate the yield and lifetime of positronium (Ps) in three different samples of per‐fluorinated sulfonic acid/polytetrafluoroethylene (PTFE) proton exchange membranes. The high probability of Ps formation enables the study of the hole volume size by the PAL technique and explains the mechanism of both methanol permeation and proton conductivity of the membranes in relation to the relative humidity (RH). The influence of various membrane parameters, including water uptake, proton conductivity, and mechanical properties, was studied. The concentration of water molecules and SO3−–H3O+groups is correlated with the ion exchange capacity (IEC) of the membranes where higher IEC leads to high absorbance of water. The proton conductivity is enhanced by increasing the IEC value of the membrane. The activation energies of decomposition temperature for the F‐950 membrane are the lowest (Eb = 2.856 and 1.030 eV for the 1st and 2nd decomposition peaks, respectively, implying that the membrane with high IEC is thermally less stable. With increasing the IEC of the membranes, the concentration of the water molecules/SO3 group increases. In addition, the proton conductivity of the membrane is positively influenced by increasing water content at high RH. The fact that the variations in hole volume size and both methanol permeability and proton conductivity are highly dependent on RH suggests that hole volume size plays an important role in many parameters of hydrated perfluorinated sulfonic acid/PTFE proton exchange membranes. The outcomes data were introduced and interpreted appropriately with a theoretical model and compared with the literature.

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Section: Resultssupporting

confidence: 90%

{Young}^{'} normals modulus ((), MPa) goodbreak= \frac{Stress ((), MPa)}{Strain} .

Section: Methodsmentioning

confidence: 99%

P ((), m^{2} / s) = {mLV}_{B} / {SC}_{A},

Section: Methodsmentioning

confidence: 99%

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Humidity effect on the transport properties of per‐fluorinated sulfonic acid/PTFE proton exchange membranes: Positron annihilation study

El-Sharkawy

Mohamed

Hassanien

et al. 2021

Polymers for Advanced Techs

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“…The nanometer-sized free volume holes in polymers, which impact the physical and chemical properties, can be investigated with positron annihilation lifetime (PAL) technique. 4,5,[39][40][41][42][43] This technique depends on the fact that a portion of the positrons infused into a polymer con-…”

Section: Positron Annihilation Lifetimementioning

confidence: 99%

Study of the nanostructure of free volume and ionic conductivity of polyvinyl alcohol doped with NaI

Hmamm

Zedan

Hamed

et al. 2020

Polymers for Advanced Techs

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Positron annihilation lifetime (PAL), AC conductivity, and impedance spectroscopy have been applied for the investigation of polyvinyl alcohol (PVA) doped with different concentrations of NaI in the range from zero to 25 wt%. Wide‐angle x‐ray diffraction measurements reveal that the addition of NaI to the PVA structure leads to a decrease in the crystallinity of the sample. The free volume size obtained from PAL measurements increases with the increase of the NaI concentration on PVA. NaI acts as an inhibitor of positronium formation on the doped polymer with inhibition constant of 0.028 (Mol%)−1. The ionic conductivity of the investigated sample was found to be correlated with the free volume size, which indicates the major role of free volume in the conduction mechanism. The AC conductivity of the prepared samples is measured at room temperature in the frequency range from 50 Hz to 5 MHz. The calculated values of frequency exponent s indicate the hopping mechanism in ionic conductivity. Impedance spectroscopy of PVA doped with different concentrations of NaI was studied. The appeared semi‐circle, in the Nyquist plot, denotes the bulk influence of PVA with different concentrations of NaI. This has been attributed to the parallel connection of bulk resistance and bulk capacitance. Also, the semi‐circle radius of Cole‐Cole plots was found to decrease with the increase of the concentration ratio (wt%) of NaI. So, the increase of the conductivity of PVA with the increase of NaI contents has been investigated.

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“…Most of the studied amino acid derivatives were methyl esters in order to prevent the hypothetically possible formation of anhydrides; anhydride formation was reported for pure Nafion. [ 44, 45 ] Taurine was used in its nonhindered form as a model amine bearing sulfo group. Besides that, water (demineralized, ca.…”

Section: Methodsmentioning

confidence: 99%

Nafion modified with simple bases and amino acid derivatives: Survey of physical properties and search for effective pervaporation membranes

Kludský

Dendisová

Hrdlička

et al. 2021

Polymer Engineering & Sci

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Nafion, a solid perfluorinated polymeric sulfonic acid, reacts readily with bases and can thus be converted to a tremendous number of individual modifications. A survey of spectral, mechanical, thermal, and pervaporation characteristics of Nafion modified with simple inorganic and organic bases and with the derivatives of amino acids is thus reported. The spectral characteristics, thermal stability, and Tg changed pronouncedly for Nafion modified with the stronger bases, such as ammonium or tris(hydroxymethyl)aminomethane, while minor changes were observed for Nafion modified with the derivatives of amino acids. Permeability and selectivity of Nafion observed for the pervaporation of methanol–dimethyl carbonate and methanol–methyl acetate mixtures were mainly influenced by the modification with amines bearing hydroxyl and, most pronouncedly, sulfo groups. Importantly, the pervaporation membrane from Nafion modified with taurine appeared similarly permeable and hygroscopic but more methanol‐selective than that from pure Nafion.

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Characterization and evaluation of Nafion HP JP as proton exchange membrane: transport properties, nanostructure, morphology, and cell performance

Cited by 20 publications

References 79 publications

Humidity effect on the transport properties of per‐fluorinated sulfonic acid/PTFE proton exchange membranes: Positron annihilation study

Humidity effect on the transport properties of per‐fluorinated sulfonic acid/PTFE proton exchange membranes: Positron annihilation study

Study of the nanostructure of free volume and ionic conductivity of polyvinyl alcohol doped with NaI

Nafion modified with simple bases and amino acid derivatives: Survey of physical properties and search for effective pervaporation membranes

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