2-Acrylamido-2-methyl-1-propanesulfonic Acid Grafted Poly(vinylidene fluoride-co-hexafluoropropylene)-Based Acid-/Oxidative-Resistant Cation Exchange for Membrane Electrolysis

Abstract

For developing acid-/oxidative-resistant aliphatic-polymer-based cation-exchange membrane (CEM), macromolecular modification of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) was carried out by controlled chemical grafting of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS). To introduce the unsaturation suitable for chemical grafting, dehydrofluorination of commercially available PVDF-co-HFP was achieved under alkaline medium. Sulfonated copolymer (SCP) was prepared by the free radical copolymerization of dehydofluorinated PVDF-co-HFP (DHPVDF-co-HFP) and AMPS in the presence of free radical initiator. Prepared SCP-based CEMs were analyzed for their morphological characteristics, ion-exchange capacity (IEC), water uptake, conductivity, and stabilities (mechanical, chemical, and thermal) in comparison with state-of-art Nafion117 membrane. High bound water content avoids the membrane dehydration, and most optimal (SCP-1.33) membrane exhibited about ∼2.5-fold high bound water content in comparison with that of Nafion117 membrane. Bunsen reaction of iodine-sulfur (I-S) was successfully performed by direct-contact-mode membrane electrolysis in a two-compartment electrolytic cell using different SCP membranes. High current efficiency (83-99%) confirmed absence of any side reaction and 328.05 kJ mol-H2(-1) energy was required for to produce 1 mol of H2 by electrolytic cell with SCP-1.33 membrane. In spite of low conductivity for reported SCP membrane in comparison with that of Nafion117 membrane, SCP-1.33 membrane was assessed as suitable candidate for electrolysis because of its low-cost nature and excellent stabilities in highly acidic environment may be due to partial fluorinated segments in the membrane structure.

Toward improved mechanical strength, oxidative stability and proton conductivity of an aligned quadratic hybrid (SPEEK/FPAPB/Fe3O4-FGO) membrane for application in high temperature and low humidity fuel cells

“…Also, the backbone chains of uorinated polymers enable the PEM to retain high compatibility with uorinated binders, such as PTFE and Naon, assisting in the construction of highly durable MEA with low cell resistance. [18][19][20] Inspired by such unique properties, uorinated polymers are being extensively studied in PEM reinforcement processes.…”

Structures and properties of polymers in ion exchange membranes for hydrogen generation by water electrolysis

“…These are all well-known membrane forming polymers, and they have been extensively studied for other PEM applications (such as fuel cells). [88][89][90] For example, Pandey et al 91 used low-cost PVDF-co-HFP as a base membrane material, and carried out the modification of its dehydrofluorinated form by incorporation of 2-acrylamido-2-methyl-1-propanesulphonic acid via controlled chemical grafting by using 2,2 0 -azobis(2-methylpropionitrile) (Figure 12). This grafted moiety is known to possess a functionally charged character as well as high ability toward proton conduction.…”

Synergistic Effect of 2-Acrylamido-2-methyl-1-propanesulfonic Acid on the Enhanced Conductivity for Fuel Cell at Low Temperature

“…Proton exchange membranes based on the aliphatic AMPS modified SPEES were synthesized using thermal copolymerization of AMPS and SPEES through sulfonamide formation, as shown in Scheme 1. After addition of TiCl 3 •AA and AlEt2Cl (25 wt% in toluene), the self-polymerization of AMPS [25][26][27][28][29] was conducted at 70 • C for 90 min, and then the reaction mass was quenched into methanol [32,33]. The product was filtrated and washed with methanol for several times and then dried at room temperature.…”

“…As an aliphatic polar monomer, AMPS has been recently used for the preparation of polyelectrolyte for a few applications [22][23][24][25], because of its good thermal, chemical, and flexible properties. Polymerization of ionic liquid-AMPS (IL-AMPS) with a reactive surfactant produced polymers with high ionic conductivity suitable for the sensor, fuel cell, and battery applications [25][26][27][28][29][30][31][32][33][34]. The pristine PAMPS derivatives are, however, generally too weak in mechanical strength in water, illustrating hydrogel properties.…”