Radiation grafting of binary monomers for the preparation of organic/inorganic hybrid membrane for proton exchange membrane fuel cell application

Radiation-Grafted Membranes for Polymer Electrolyte Fuel Cells: Current Trends and Future Directions

“…The durability of radiation-grafted PEMs was found to vary significantly depending on the starting polymeric materials, the composition of the monomer system, the RIG technique employed, reaction parameters, and not least the method of assembling the membrane with the electrodes. ,,− A number of new preparative routes for introducing substantial improvements in the stability of the desired PEMs have been proposed. These include three main strategies: (i) the grafting of alternative monomers such as m , p -methylstyrene or vinyltoluene, , p - tert -butylstyrene, vinylbenzyl chloride, , p -styryltrimethoxysilane, , methyl acrylate, and 2-bromotetrafluoroethyl trifluorovinyl ether and monomer combinations such as styrene/α-methylstyrene, styrene/acrylonitrile, styrene/methylacrylnitrile, ,,, styrene/acrylic acid, ,, styrene/methyl methacrylic acid, α-methylstyrene/methylacrylnitrile, , styrene/glycidyl methacrylate, , styrene/trimethoxysilylpropyl methacrylate, and methyl acrylate/methyl methacrylate; (ii) the introduction of new or modified substrate films for grafting of styrene or its derivatives with or without cross-linkers such as cross-linked PTFE, ,,,,,,,− engineering plastics such as poly­(ether ether ketone), ,− polyimide, , polyether sulfone, alicyclic polybenzimidazole, polymer powder (e.g., UHMWPE or PVDF) followed by thermal treatment, − or solution casting, porous films, ,,,​ − and nanofibrous mats; and finally (iii) the application of n...…”

“…19,33,39a−c A number of new preparative routes for introducing substantial improvements in the stability of the desired PEMs have been proposed. These include three main strategies: (i) the grafting of alternative monomers such as m,p-methylstyrene or vinyltoluene, 139,143 p-tert-butylstyrene, 139 vinylbenzyl chloride, 144,146 p-styryltrimethoxysilane, 148,263 methyl acrylate, 174 and 2-bromotetrafluoroethyl trifluorovinyl ether 152 and monomer combinations such as styrene/α-methylstyrene, 156 styrene/ acrylonitrile, 155 styrene/methylacrylnitrile, 155,157,159,264 styrene/ acrylic acid, 65b,153,154 styrene/methyl methacrylic acid, 164 αmethylstyrene/methylacrylnitrile, 156,157 styrene/glycidyl methacrylate, 163,165 styrene/trimethoxysilylpropyl methacrylate, 265 and methyl acrylate/methyl methacrylate; 174 (ii) the introduction of new or modified substrate films for grafting of styrene or its derivatives with or without cross-linkers such as cross-linked PTFE, 62g,i,j,122b,127,142,156,179−181 engineering plastics such as poly(ether ether ketone), 169,171−173 polyimide, 178a,187 polyether sulfone, 178b alicyclic polybenzimidazole, 196 polymer powder (e.g., UHMWPE or PVDF) followed by thermal treatment, 197−199 or solution casting, 200 porous films, 61,186,187, 189−193 and nanofibrous mats; 201 and finally (iii) the application of new RIG methods including the direct sulfonation of polymer films, 6 4 a , 6 8 , 2 0 2 , 2 0 5 − 2 0 8 double cross-linking, 62g,i,j,122b,127,142,156,179−181 pore-filling of porous substrates, 48,61,186−193 combining RIG with mediated living radical grafting, 209−212 single-step grafting, 213−217 patterned grafting, 218−220 and RIG with combined in situ sol−gel reaction 221 and the modification of Nafion membranes. 62n,222 Cross-linked PEMs prepared by the RIG of styrene and cross-linkers such as DVB TAC and BVPE or their mixtures followed by sulfonation were tested for a few thousand hours, and results showed great potential for commercialization.…”

Investigation of chemical degradation and water states in the graft‐type polymer electrolyte membranes

“…[23] The water molecules are found to bind tightly to the sulfonic acid groups at the surface of channels and clusters to form solvation shells. [24] In the membranes, the water states are generally classified into four types including protonated water, water H-bonded to sulfonic acid groups, water H-bonded to other water molecules, and non-H-bonded water molecules. [25][26][27] The last one may be trapped at the free volume holes of polymers without hydrogen or water bonds.…”

Crosslinking effects on hybrid organic-inorganic proton conducting membranes based on sulfonated polystyrene and polysiloxane

“…Physical crosslinking can be accomplished by combining an ionomeric polymer with another polymer, giving rise to different types of blends that are identified according to the nature of the interaction (van der Waals, dipole, hydrogen bond and acid–base) responsible for the entanglement of the polymers. Hybrid materials formed by organic and inorganic components, obtained both by covalent and physical crosslinking, are very attractive for membrane synthesis because they can combine basic properties of organic and inorganic materials, resulting in an improved type of membrane with significant potential because these materials show a positive synergistic effect when compared with the single materials used separately . Organic materials have important limitations associated with mechanical, chemical and thermal stability; however, the flexibility and low cost of polymers make them highly interesting for many applications.…”