Polybenzimidazole


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Polybenzimidazole

 

a polymer containing benzimidazole rings in the main macromolecular chain:

where R = H, C6H5, or an alkyl.

Polybenzimidazoles are produced mainly by solid-phase poly-cyclic condensation of aromatic tetraamines with diphenyl esters of aliphatic or aromatic dicarboxylic acids. Of current practical importance are polybenzimidazoles based on aromatic acids (mainly o,o′-diaminobenzidine and diphenyl isophthalate), called aromatic polybenzimidazoles:

Most polybenzimidazoles are colorless or slightly colored amorphous or crystalline compounds, depending on their structure, with molecular weights up to 40,000. They have high heat resistance: rapid decomposition of aromatic polybenzimidazoles in air begins at 450°-600°C, and of aliphatic polybenzimidazoles, at 300°-400°C. Polybenzimidazoles are also characterized by high chemical stability and, in particular, resistance to hydrolysis—for example, some polybenzimidazoles are unchanged upon boiling in 70-percent H2 SO4 and 25-percent NaOH for 10 hr.

Polybenzimidazoles made from aliphatic polymethylene dicarboxylic acids (for example, sebacic acid) are superior in strength to the aromatic polybenzimidazoles. The latter are soluble, for example, in dimethylacetamide.

Polybenzimidazoles are used to make adhesives, heat-resistant films and fibers, binders for glass-fiber-reinforced plastics used in the construction of airplanes and rockets, antifriction materials, and ablation heat-shielding coatings for spacecraft. Fabrics made from polybenzimidazoles have high resistance to heat and fire and are hydrophilic, comfortable to wear, and resistant to abrasion.

Polybenzimidazoles are produced in the USA. An adhesive produced under the name Imidite 850 and a binder for glass-fiber-reinforced plastics under the name Imidite 1850 are produced from polybenzimidazoles.

M. M. TEPLIAKOV

References in periodicals archive ?
Savadogo and Rodriguez [15] reported 100% C[O.sub.2] using Nafion and polybenzimidazole polymer electrolytes.
Her thesis, which was funded by US based Trevi Systems, explored the development of a desalination membrane that utilizes the unique chemical and thermal strength of the material polybenzimidazole (PBI), with the chemical phenomenon known as phase-inversion, whereby removal of the solvent from a liquid-polymer solution produces a porous and solid membrane.
Ten chapters review the chemistry, manufacturing processes, properties, and primary industrial uses of polyarylethersulfones and polyaryletherimides, semi-aromatic polyamides, polyphenylene sulfide, polyaryetherketones, polymideimides, polyimides, polybenzimidazole, liquid crystal polyesters, polyphenylenes, and perfluoropolymers.
It is knit and consists of polybenzimidazole (PBI) fibers that are also used in firefighting gear.
film formation, thermal treatments are performed to remove the solvent and promote membrane properties.The thickness of the prepared hybrid polybenzimidazole (PBI)/silica membranes is about 40 micrones.Regarding the emerging markets for membrane gas separations all around the world and especially its extended markets in Iran, demands from oil, gas and petrochemical industries, enhancement of these membranes with the help of nanotechnology is among the hottest research topics."We have aimed to mass-produce and commercialize polymer nanomembranes since our research company, Parsian Pouya Polymer, was established," Sadeqi, a lecturer at Isfahan University of Technology told INIC.
A new technical brochure from Victrex highlights the key features of these proprietary blended products based on Victrex PEEK polymer and Celazole polybenzimidazole. To illustrate the products' mechanical performance vs.
The FDNY currently outfits it members with a hood that is made up of a double knit fabric that is a blend of 20% PBI (polybenzimidazole, synthetic rayon fiber) and 80% Lenzing (flame resistant synthetic fiber).
The fuel cell uses a Polybenzimidazole membrane and electrodes manufactured in CIDETEC's laboratories.
The MEA consists of catalysts, gas diffusion layers, and the Celtec membrane, made with the company's temperature-resistant polymer polybenzimidazole. This membrane is permeable to protons and has electrodes on both sides.
They chemically modified polybenzimidazole, a plastic used to make fibers in protective clothing for firefighters and racecar drivers.
The products are pseudo-thermoplastics formed from polybenzimidazole (PBI), a polymer resin that does not burn in air.
Kharul, "Selective interfacial synthesis of metal-organic frameworks on a polybenzimidazole hollow fiber membrane for gas separation," Nanoscale, vol.