Effect of Functional Phosphonic Groups Grafted on the Silica Surface on the Properties of Hybrid Membranes Based on Polybenzimidazole PBI-O-PhTстатья
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Дата последнего поиска статьи во внешних источниках: 3 ноября 2021 г.
Аннотация:Hybrid membranes based on polybenzimidazole PBI-O-PhT with incorporated particles of silicon dioxide functionalized with phosphonic groups have been synthesized. The membranes have been prepared in situ by casting a polymer solution with a precursor for particle synthesis. The precursor was a mixture of tetraethoxysilane and (2-diethylphosphatoethyl)triethoxysilane. The mass concentration of the dopant was 5 or 10 wt %, and the mole fraction of functional groups on the oxide surface was varied in the range of 0–100 mol % by changing the composition of the precursor mixture. The resulting membranes have been characterized using transmission and scanning electron microscopy, IR spectroscopy, and impedance spectroscopy. Grafting of functional –PO3H2 groups onto the silica surface leads to a significant increase in the uptake of phosphoric acid by hybrid membranes, the content of which determines the functional properties of these materials. An increase in the number of –PO3H2 groups leads to both an increase in the degree of acid doping and ionic conductivity. The conductivity of the best samples obtained reaches 0.081 S/cm at 160°C. The introduction of acid groups on the dopant surface is a promising approach from the point of view of reducing the amount of phosphoric acid required to maintain a high proton transport rate.