Some aspects of polybenzimidazoles’ synthesis in P2O5 containing condensation media

Synthesis and characterization of fluorene‐based polybenzimidazole copolymer for gas separation

“…Unfortunately, the homopolymer was weak and fragile, so that its permeability could not be measured because it was damaged when placed in the measuring cell. To improve the strength of the membrane, 4,4′‐oxybis(benzoic acid) (OBBA) was selected as a monomer (Scheme ), and the resulting polymer showed good mechanical characteristics for gas permeation test . The CPBI copolymer (CPBI‐coXY) structure is shown in Scheme and Figure .…”

“…To improve the strength of the membrane, 4,4 0 -oxybis(benzoic acid) (OBBA) was selected as a monomer (Scheme 3), and the resulting polymer showed good mechanical characteristics for gas permeation test. 7,8 The CPBI copolymer (CPBI-coXY) structure is shown in Scheme 3 and Figure 2. The hydrogen atom of the OBBA unit, which is not seen in the CPBI homopolymer, appears at 7.30, 7.87, and 8.30 ppm in the copolymers, and the peak increases with the relative amount of OBBA.…”

“…6 PBIs are a group of membrane polymers that can be manufactured by condensation polymerization between a monomer with four amine groups, such as 3,3 0 -diaminobenzidine (DAB), and one of several other suitable monomers, e.g., isophthalic acid, terephthalic acid, 4,4 0 -oxybis(benzoic acid), or diphenyl isophthalate (Scheme 1). [7][8][9] Alternatively, poly(2,5-benzimidazole) (ABPBI, Scheme 1) offers excellent mechanical strength, and it can be made from a single monomer using a simple synthetic method. 10 However, the extremely high crystallinity of this polymer renders it insoluble in most organic solvents.…”

Design and Synthesis of Cross-Linked Copolymer Membranes Based on Poly(benzoxazine) and Polybenzimidazole and Their Application to an Electrolyte Membrane for a High-Temperature PEM Fuel Cell

“…PBI also has four carbons at the unobstructed ortho position of the benzene ring (the asterisk in PBI, Figure 1a). In this case, the reactivity should be close to or exceed that of the benzoxazine due to the electron-withdrawing imidazole groups [112,113]. Therefore, we assumed that the peripheries of the carbons (marked by the asterisk in Figure 1a) of the benzene rings in the PBI could covalently react with the methylene groups of pBUa (Figure 4c).…”

High performance polybenzimidazole based asymmetric hollow fibre membranes for H2/CO2 separation

“…It is known that PBI prepared by melt polycondensation has disadvantages such as thermal crosslinking, incomplete cyclisation, high plugging values, etc. Moreover, in order to get high molecular weight of PBI by melt polycondensation temperature above 400 • C, use of catalysts and sophisticated equipments are required [34]. In the present study, we have employed the conventional solution polycondensation method for PBI synthesis developed by Iwakura et al [35].…”