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Poly 2,2- 5-bibenzimidazole

Poly-2-2 -(w-phenylene)-5,5 -bibenzimidazole, commonly called polybenzimidazole (PBI), was developed under the aegis of the U.S. Air Force Materials Laboratory in cooperation with the then-existing Celanese Corporation. The fiber went into commercial production in the United States in 1983. It is a condensation polymer obtained from the reaction of tetra-aminobiphenyl and diphenylisophthalate in a nitrogen atmosphere at temperatures that may reach 400°C in the final stages.29 The structure of a repeating unit is shown below. [Pg.484]

FIGURE 27.70 Chemical structure of poly[2,20-(w-phenylene)-5,50-bibenzimidazole]. [Pg.811]

Fig. 3.3 Molecular structure of Celazole (poly-2,2 -m-(phenylene)-5,5 -bibenzimidazole)... Fig. 3.3 Molecular structure of Celazole (poly-2,2 -m-(phenylene)-5,5 -bibenzimidazole)...
N[non-amide -(NH)- unit] refers to the -(NH)- moieties in some rather rare polymers such as polybenzimidazoles, where there is no carbonyl group adjacent to the -(NH)- unit. For example, poly[2,2 -(m phenylene)-5,5 -bibenzimidazole] (Figure 5.2) has two -(NH)- moieties not adjacent to carbonyl groups in its repeat unit. An -NH2 (i.e., -NH-H) unit without an adjacent carbonyl unit, terminating a side group, is also counted in N[non.amjdc (nh) unit]- As mentioned above, -(NH)- units in urethane groups are also counted as non-amide -(NH)- units. [Pg.185]

Figure 5.2. Schematic illustrations of the repeat units of several polymers discussed in the text, in the context of structural correction terms used in the correlations for the cohesive energy in sections 5.B and 5.C. (a) Poly[2,2 -(m-phenylene)-5,5 -bibenzimidazole]. (b) Bisphenol-A... Figure 5.2. Schematic illustrations of the repeat units of several polymers discussed in the text, in the context of structural correction terms used in the correlations for the cohesive energy in sections 5.B and 5.C. (a) Poly[2,2 -(m-phenylene)-5,5 -bibenzimidazole]. (b) Bisphenol-A...
Aromatic PBIs are highly thermostable, with melting points >600°C. The PBI commercially available is poly[2,20-(mphenylene)-5,50-bibenzimidazole] (cf. Figure 21.49). [Pg.602]

These fibre-formimg polymers are so-called ladder polymers and possess wholly aromatic polymer chains. The two common examples available commercially are the polybenzimidazole FBI (Intertek, formerly Celanese) with the full chemical name poly (2,2 -(m-phenylene)-5,5 -bibenzimidazole) and the polybenzoxazole Zylon (Toyobo) with the full chemical name polyfpara-phenylene benzobisoxazole) and generic acronym PBO. Their similarity in polymer chain stractures and high degrees of... [Pg.259]

Other group of ionomers for PEM fuel cells are based on polymers, such as poly [2,2 -(m-phenylene)-5,5 -bibenzimidazole] (m-PBI), obtained by polymerization of 3,3 -diaminobenzidine, 1,2,4,5-tetraaminobenzene and a variety of aromatic diphenyl dicarboxylates [189], whose structure is shown in Fig. 6.10. This non-ionic polymer becomes a proton conductor when doped with a strong acid such as sulphuric or phosphoric acid. [Pg.134]

Lobato J, Canizares P, Rodrigo MA, Linares JJ, Manjavacas G (2006) Synthesis and characterization of poly[2,2-(m-phenylene)-5,5-bibenzimidazole] as polymer electrolyte membrane for high temperature PEMFCs. J Membr Sci 280 351-362... [Pg.225]

Nanocomposites from (poly[2,2 -(p-oxidiphen-ylene)-5,5 -bibenzimidazole]) and polyhedral oligomeric silsesquioxane (POSS) with a pendant phenyl group have been prepared by an in situ polymerization of 4,4 -dicarboxydiphenyl ether and 3,3 -diaminobenzidine in the presence of POSS [21]. The PBI chains were successfully attached to the phenyl group of the POSS by aFriedel-Crafls reaction. [Pg.375]

Poly(2,2 -( 1,4-phenylene)5,5 -bibenzimidazole) can be obtained under certain conditions of polymerization as a high-molecular-weight species [29]. The polymer solutions can be used directly for phosphoric acid doped PBI membranes. Such membranes show high phosphoric acid doping levels. At 160 °C a high carbon monoxide tolerance for fuel cells is observed. [Pg.376]

Yu S, Zhang H, Xiao L, Choe EW, Benicewicz BC. Synthesis of poly (2,2 -(L4-phenylene) 5,5 -bibenzimidazole) (para-pbi) and phosphoric acid doped membrane for fuel cells. Fuel Cells 2009 9(4) 318-24. [Pg.379]

A variety of high-temperature-resistant PBIs were synthesized and reported in the Uterature. The most widely used PBI is poly[2,2 -(l,3-phenylene)-5,5-benzimidazole] (known as m-PBI) [22]. The other variations are poly[2,2 -( 1,4- phenylene)-5,5 -benzimidazole] (known as p-PBI) [13], poly(4,4 -diphenylether-5,5 -bibenzimidazole) (OPBI) [23], poly(2,5-benzimidazole) (AB-PBI) [24], pyridine-based PBI [25], sulfonated PBI [26], hyperbranched polybenzimidazole (HPBI) [27], naphthalene-based PBI [28], fluorinated PBI [29], PBI block copolymer [30], sulfonated PBI copolymer with sulfone or sulfonic acid groups in the backbone [31,32], PBFnano-composite [33], cross-linked PBI [34], and many others. Different approaches have been taken by the researchers to modify the structure and properties of the fluorinated PBI. A detailed summary of these works is discussed below. [Pg.229]


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See also in sourсe #XX -- [ Pg.355 , Pg.357 , Pg.358 , Pg.359 , Pg.360 ]




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