| 摘要 |
Polybenzimidazoles consisting of recurring units of the formula <FORM:1107440/C3/1> wherein the pyridyl radical is connected to the imidazole linkage either at the 2 or 3 position are prepared by heating 3,31,4,41-tetramino-diphenylmethane with a diester of the formula <FORM:1107440/C3/2> or a mixture thereof, where R is phenyl or phenyl-phenyl in the absence of oxygen at 160 DEG C. to 230 DEG C. to form a prepolymer, and heating the prepolymer at 260 DEG C. to 320 DEG C. until the polybenzimidazole is formed. More preferably the prepolymer is comminuted and then heated to a temperature between 260 DEG C. and 320 DEG C. until the polymer formed has a reduced viscosity of at least 0.5 H/g. as determined on a solution of 0.5 g. of polymer in 100 millilitres of 90% formic acid at 25 DEG C.. The prepolymer may be heated in the presence of an inert solvent such as N-methyl pyrrolidone, silicone oil or a eutectic mixture of diphenyl and diphenyl oxide. The polybenzimidazoles can be spun into filaments or used to form films using dimethylsulphoxide or N,N-dimethylformamide as solvents. Reference has been directed by the Comptroller to Specification 1,003,291.ALSO:3,31,4,41 - Tetramino - diphenyl methane may be prepared by reacting ortho-nitroaniline with formaldehyde to give methylene bis-(orthonitroaniline) which is stirred with concentrated hydrochloric acid and hydrogen chloride gas is bubbled therethrough to produce bis-(4-amino-3-nitrophenyl)methane which is reacted with tin and hydrochloric acid to give the desired tetramine. The phenol ester of pyridine-2,5-dicarboxylic acid is prepared by reacting pyridine-2,5-dicarboxylic acid with thionyl chloride to give the diacid chloride which is then reacted with phenol. Reference has been directed by the Comptroller to Specification 1,003,291. |
