Synthesis of N-phosphonoethylated cardo poly(benzimidazole) and testing of proton-conducting membranes made of it

Synthesis of poly(aryl ether)s bearing phosphonated side-chains from phosphonate ester-containing bisphenols

“…This could explain why the experimental values of the first weight losses are slightly higher than the theoretical ones. As mentioned elsewhere [17] , heating phosphonate esters at reflux in concentrated hydrochloric acid results in a complete hydrolysis of those groups into phosphonic acids.…”

“…A convenient approach used to introduce phosphonic acid groups along a polymer chain consists in the chemical-modification of high molecular weight pre-existing polymers. In this respect, different aromatic and heterocyclic polymer structures have been investigated, such as (poly(phosphazene)s [11][12][13][14] , poly(oxadiazoles)s [15] , poly(paraphenylene)s [16] , poly(benzimidazole) [17] , poly(diimidazopyridine)s [18] and the most extensively studied poly(aryl ether)s. Phosphonic acid groups can be incorporated by different chemical reactions (Arbusov or Michaelis-Arbusov reaction [19] , lithiation and direct phosphonation [20] , reaction with a phosphonate containing reactant [21] or a iodobenzoyl reactant [22] , by nickel-catalyzed [23,24] or palladium catalysed phosphonation [25][26][27] , N-alkylation [28] or even by polymerization of vinylphosphonic side-chains [29] ….). However, due to harsh reaction conditions (long reaction times, high temperature and low yields), such post-modifications usually induce some undesirable chain breaking or cross-linking.…”

Design of electrodes based on a carbon nanofiber nonwoven material for the membrane electrode assembly of a polybenzimidazole-membrane fuel cell

“…The synthesis of PBI-O-PHT and the production of membranes based on it were described in detail pre viously [4][5][6][7][8][9]. Testing of seven layer membranes (active area 5 cm 2 ) of the MEA in standard cells (Arbin Instruments) was performed according to a published procedure [7][8][9] using both electrodes made espe cially for this work, and commercial electrodes (PEMEAS Celtec ® Р1000).…”

“…At the Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, Russia, new competitive MEAs based on the card polymer PBI-O-PHT [4][5][6][7][8][9]:…”

Proton-Conducting Polymer-Coated Carbon Nanofiber Mats for Pt-Anodes of High-Temperature Polymer-Electrolyte Membrane Fuel Cell

“…For example, the N-ethyl phosphonated PBI-type polymer (PBI-O-PhT-P), deposited on carbon nanofibers of the anode, introduces additional phosphonic functional groups, which may presumably improve proton conductivity. Earlier, we have shown that for a membrane based on PBI-O-PhT-P (also abbreviated as PEPBI-O-PH), when operated in HT-PEM FC, the value of the open circuit voltage was quite low (0.760 V) [ 67 ]. This can be explained by some features of the chemical structure of the polymer, particularly the loosening of polymer chains by side ethylphosphonic groups.…”