Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Nafion doped with polybenzimidazole

Abstract There have been numerous studies on modifying DuPont s Nafion (a perfluorosulfonic acid polymer) in order to improve the performance of this membrane material in a direct methanol fuel cell. Modifications focused on making Nafion a better methanol barrier, without sacrificing proton conductivity, so that methanol crossover during fuel cell operation is minimized. In this chapter, a brief literature survey of such modifications is presented, along with recent experimental results (membrane properties and fuel cell performance curves) for (1) thick Nafion films, (2) Nafion blended with Teflon-FEP or Teflon-PFA, and (3) Nafion doped with polybenzimidazole. [Pg.341]

Chapter 14 presents a brief hterature survey of such modifications, along with recent experimental results (membrane properties and fuel cell performance curves) for (i) thick Nafion films, (ii) Nafion blended with Teflon -FEP or Teflon -PFA, and (iii) Nafion doped with polybenzimidazole. [Pg.441]

Another approach was the synthesis of inorganic/organic composite materials to influence the properties of the membrane. An overview on the state of the art of composite perflourinated membranes is given in [15]. Infiltration of a polymer carrier material with various inorganic proton conductors is subject of a patent [16]. For operation at elevated temperature, several materials have been considered, hi an early work, Nafion /Fl3P04 showed better conductivity at temperatures above 100°C compared with blank Nation and also reduced methanol permeabihty [17]. New types of polymers are also under development for better temperature stabihty one of the most advanced examples is the high-temperature material polybenzimidazole, which usually is doped with phosphoric acid [18]. [Pg.159]

The vast catalogue of polymeric materials reviewed here included Nafion composite with inorganic and organic fillers, and non-fluorinated proton conducting membranes such as sulfonated polyimides, poly(arylene ether)s, polysulfones, poly (vinyl alcohol), polystyrenes, and acid-doped polybenzimidazoles. Anion-exchange membranes are also discussed because of the facile electro-oxidation of alcohols in alkaline media and because of the minimizatirHi of alcohol crossover in alkaline direct alcohol fuel cells. [Pg.121]

There has been considerable research on modifying Nafion, so as to improve its properties for use in a direct methanol fuel cell. In this chapter, a review of Nafion-based DMFC membranes is presented, including a literature survey followed by recent results by the present authors on improving Nafion by (1) using thick stacked Nafion membranes, (2) blending Nafion with Teflon-FEP or Teflon-PFA, and (3) doping Nafion with polybenzimidazole. [Pg.342]

Fig. 11.12 Relationship between proton conductivity and adjoining gas stream humidity at various temperatures for Nafion (1100 EW) [5] and phosphoric acid-doped polybenzimidazole (FBI) [54]. The data clearly demonstrate that the increase in temperature from 80°C to 120°C has little effect on the conductivity of Nafion but a significant effect on the PBI systeans. A curve is also shown for a material exhibiting the desired conductivity as a function of the relative humidity that would be ideal for system simpUiication (The figure is reproduced from Gasteiger and Mathias [5] with permission from The Electrochemical Society)... Fig. 11.12 Relationship between proton conductivity and adjoining gas stream humidity at various temperatures for Nafion (1100 EW) [5] and phosphoric acid-doped polybenzimidazole (FBI) [54]. The data clearly demonstrate that the increase in temperature from 80°C to 120°C has little effect on the conductivity of Nafion but a significant effect on the PBI systeans. A curve is also shown for a material exhibiting the desired conductivity as a function of the relative humidity that would be ideal for system simpUiication (The figure is reproduced from Gasteiger and Mathias [5] with permission from The Electrochemical Society)...

See other pages where Nafion doped with polybenzimidazole is mentioned: [Pg.354]    [Pg.354]    [Pg.33]    [Pg.191]    [Pg.82]    [Pg.570]    [Pg.15]    [Pg.361]    [Pg.306]    [Pg.191]    [Pg.408]    [Pg.1090]    [Pg.220]    [Pg.343]    [Pg.44]    [Pg.356]    [Pg.440]    [Pg.529]    [Pg.569]    [Pg.227]    [Pg.297]    [Pg.159]    [Pg.376]    [Pg.1079]    [Pg.272]    [Pg.435]   
See also in sourсe #XX -- [ Pg.354 , Pg.357 ]




SEARCH



Polybenzimidazol

Polybenzimidazoles

© 2024 chempedia.info