| 摘要 |
<p>A two-stage process for the production of polybenzimidazoles is provided wherein a mixture of an aromatic tetraamine, e.g., 3,3 min ,4,4 min -tetraaminobiphenyl, a free dicarboxylic acid, e.g., isophthalic acid, and a monohydric phenolic compound, e.g. phenol, 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 rapid rise in agitator torque. 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. Polymer may be obtained by the process which has a higher inherent viscosity than when no monohydric phenolic compound is employed.</p> |
