High-temperature polymer polybenzimidazole

Xiao, L. et al.. Synthesis and characterization of pyridine-based polybenzimidazoles for high temperature polymer electrolyte membrane fuel cell applications. Fuel Cells, 5, 287, 2005. 

U.S. Air Force research program began toward the end of his first career at the University of Illinois and continued throughout his entire second career at the University of Arizona. During a 30-year period he was the principal contributor to the Air Force program on high temperature polymer synthesis. His basic research led to the commercialization of polybenzimidazole (PBI)... 

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]. 

Polybenzimidazole (PBI) is the most well-known commercial example of aromatic heterocycles used as high-temperature polymers. The synthesis of PBI is carried out as follows (see also Figure 1.36). The tetraaminobiphenyl required for the synthesis of PBI is obtained from 3,3 -dichloro-4,4 -diaminodi-phenyl (a dye intermediate) and ammonia. Many other tetraamines and dicarboxylic acids have been... 

Copolymers with benzimidazole and benzoxazole units have been prepared and used as a polymer electrolyte material [30,11]. The polymer electrolyte material has both high proton conductivity and excellent mechanical properties even when it is obtained by in situ phosphoric acid doping. The polymer electrolyte material may substitute for the conventional phosphoric acid doped polybenzimidazole in a polymer electrolyte membrane fuel cell, particularly in a high-temperature polymer electrolyte membrane fuel cell. 

Polybenzimidazole Based High Temperature Polymer Electrolytes... 

Further discussion on the general theme of high-temperature polymers and adhesives can be found in the articles entitled Polyphenylquinoxalines, Polybenzimidazoles and Polyether ether ketones. (See also article on High-temperature adhesives.)... 

G. Qian, B.C. Benicewicz, Synthesis and characterization of high molecular weight hexafluoroisopropylidene containing polybenzimidazole for high-temperature polymer electrolyte membrane fuel cells, J. Polym. Sci. Part A Polym. Chem. 47 (16) (2009) 4064-4073. 

The use of adhesives can be traced back many centuries, while the production of adhesives, on an industrial scale, started about 300 years ago. The birth of modern structural adhesives can be dated from about 1910, with the introduction of the phenol-formaldehyde resins.Table II summarizes the historical development of structural adhesives, with the dates referring to the approximate time period during which each adhesive became commercially available. The introduction dates for the high-temperature polymers (polyimide, polybenzimidazole, and polyquinoxa-line) have been included for reference, although, as previously mentioned, there are presently few commercial products based on these polymers. 

Polybenzimidazoles first appeared in US Patent 2,895,948 in 1959. In 1961, Vogel and Marvel opened the field of high temperature polymers [1] with their studies of the thermal stability of aromatic polybenzimidazoles [3]. Subsequently, AFML and NASA funded programs for basic studies and for structural and textile applications of polybenzimidazoles to meet new aircraft and aerospace material needs. Several reviews were published [4-7]. Structural applications of polybenzimidazoles are still in developmental stages which is discussed below. One polybenzimidazole polymer (PBI) which was developed for fiber applications is now commercial. Details of the polymer synthesis and fiber process are described in the next section. 

Polybenzimidazole polymers can be formed in the melt or in solution. Mechanistic studies have proposed Schiff s base or aminoamide intermediates. Recent texts on high temperature polymers discuss benzimidazole reaction mechanisms with references to original works [1.2]. 

Berber MR, Fujigaya T, Sasaki K et al (2011) Remarkably durable high temperature polymer electrolyte fuel cell based on poly(vinylphosphonic acid)-doped polybenzimidazole. Sci Rep 3 1-7... 

Li X, Chen X, Benicewicz BC (2013) Synthesis and properties of phenylindane-containing polybenzimidazole (PBI) for high-temperature polymer electrolyte membrane fuel cells (PEMFCs). J Power Sources 243 796-804... 

Wang JTW, Hsu SLC (2011) Enhanced high-temperature polymer electrolyte membrane for fuel cells based on polybenzimidazole and ionic liquids. Electrochim Acta 56 2842-2846... 

Casting by solvent evaporation is a commonly used procedure for fabrication of membranes based on organic polymers. It is probably the most widely used technique for polybenzimidazole membrane preparation for high-temperature polymer electrolyte membrane fuel cells. After casting, doping with phosphoric acid provides proton conductivity to the membrane. 

Aili D, Allward T, Alfaro SM et al (2014) Polybenzimidazole and sulfonated polyhedral oligosilses-quioxane composite membranes for high temperature polymer electrolyte membrane fuel cells. Electrochim Acta 140 182-190... 

Pinar FJ, Rastedt M, Pilinski N et al (2014) Effect of compression cycling on polybenzimidazole-based high-temperature polymer electrolyte membrane fuel cells. Fuel Cells 15(1) 140-149... 

Fig. 7.14 Temperature dependence of proton conductivity of a 2,5-PPBI membrane with 20.4 mol H3PO4 doping. Reprinted with permission from Ref. [54] L. Xiao, et al.. Synthesis and characterization of pyridine-based polybenzimidazole for high temperature polymer electrolyte membrane fuel cell application. Fuel Cell, 5, 287-295 (2005). Copyright Wiley-VCH...

Xiao, L., H. Zhang, T. Jana, E. Scanlon, R. Chen, E. W. Choe, L. S. Ramanathan, S. Yu, and B. C. Benicewicz, Synthesis and characterization of pyridine-based of polybenzimidazoles for high temperature polymer electrolyte membrane fuel cell applications . Fuel Cells 5(2) (2005) 287-295. 

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