Benzimidazole polymers

M. Kawahara, M. Rikukawa, K. Sanui, Relationship between absorbed water and proton conductivity in sulfopropylated poly(benzimidazole). Polymers for Advanced Technologies 2000, 11,544-547. 

Poly(2,5-benzimidazole) (ABPBI) is the simplest benzimidazole polymer (see Fig. 6.10) with a higher affinity towards H3PO4 than PBI, and it can be polymerized from a single, inexpensive, commercial monomer (DABA) [442]. 

Asensio JA, Smchez EM, G6mez-Romero P (2010) Proton-conducting membranes based on benzimidazole polymers for high-temperature PEM fuel cells. A chemical quest. Chem Soc Rev 39 3210-3239... 

Tetraaniinobiphenyl (3,3 -diaminobenzidine), produced from o-chloro nitrobenzene, is used in the manufacture of high-temperature resistant benzimidazole polymers (PBI), which are produced by reaction with diphenyl isophthalate (Hoechst-Celanese),... 

Polybenzimidazoles are a class of thermally stable polymers, typically condensed from aromatic bis-o-diamines and dicarboxylates. The namesake polymer repeat unit, which contains a 1,3-dinitrogen heterocycle, is benzimidazole. As a monomer, benzimidazole, has a melting point of 170°C and a boiling point of >360°C. Benzimidazole s hydrocarbon analog, indene, has a melting point of -2°C and a boiling point of 183°C. With only a molecular weight difference of 2, the differences in thermal behavior between benzimidazole and indene foretells some of the unusual thermal characteristics to be found in benzimidazole polymers. 

Polybenzimidazoles are synthesized from aromatic tetraamines (bis-o-diamines) and dicarboxylates (acids, esters or amides). Generalized monomers are shown in FIGURE 1 and polybenzimidazoles from those monomers are shown in FIGURE 2. In either figure, R(l) and R(2) can be aromatic or aliphatic and may contain other groups as ether, ketone, sulfone, etc. The structures shown do not exhaust all possible benzimidazole polymers. 

Nalawade A, Hassan MK, Jarrett WA et al (2011) Broadband dielectric spectroscopy studies of glassy-state relaxations in annealed poly (2,5-benzimidazole). Polym Int 61 55-64... 

Other types of benzimidazole polymers where the imidazole hydrogen was substituted with a phenyl group or an arylene group such as in structures 1 and 2 respectively have, also been evaluated as adhesives. 

Essentially no new adhesive work has been reported on benzimidazole polymers over the... 

A variation of a benzimidazole polymer is the polybenzimidazoquinazoline" of representative structure 3. In small composites, this ma-... 

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