| 摘要 |
A two stage process for the production of polybenzimidazoles and a novel polybenzimidazole produced there by is provided wherein a mixture of an aromatic tetraamine, e.g., 3,3',4,4'-tetraaminobiphenyl and a free dicarboxylic acid, e.g., isophthalic acid, is heated with agitation in a first stage to a temperature above the melting point of the tetraamine until the viscosity of the mixture rises as indicated by an agitator torque of at least 1.5 times that before the rise in viscosity. The agitation is then discontinued and the reaction mixture is allowed to foam while heating is continued. The foam is then allowed to cool to a friable mass and is crushed to a ground prepolymer which is heated with agitation in a second stage until the desired polymer is obtained. The novel polybenzimidazole produced is the reaction product of phenylindandicarboxylic acid and 3,3',4,4'-tetraaminobiphenyl.
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