Method of making polybenzimidazole

Abstract

A method of making a polybenzimidazole (PBI) includes the steps of: reacting, in a solution, an organic compound having at least 2 amino groups with an organic aldehyde adduct, the reactants comprise at least 8% by weight of the solution. A solvent of the solution may be selected from the group of: N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), tetramethylene sulfone, and combinations thereof. The organic aldehyde adduct may be an organic aldehyde bisulfite adduct. The organic aldehyde portion of the organic aldehyde adduct being aliphatic, alicyclic, aromatic, heterocyclic, or heteroaromatic aldehyde or mixtures thereof. The polybenzimidazole may have an intrinsic viscosity of at least 0.40 dl/g.

We claim: 
     
         1 . A method of making a polybenzimidazole comprising the steps of:
 reacting, in a solution,
 an organic compound having at least 4 amino groups with 
 an organic dialdehyde adduct, the reactants comprise at least 8% by weight of the solution. 
   
     
     
         2 . The method of  claim 1  where a solvent of the solution being selected from the group consisting of: N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), tetramethylene sulfone, and combinations thereof. 
     
     
         3 . The method of  claim 1  wherein the organic dialdehyde adduct being an organic dialdehyde bis (bisulfite) adduct. 
     
     
         4 . The method of  claim 3  wherein the bisulfite portion of the organic aldehyde bisulfite adduct being a bisulfite salt. 
     
     
         5 . The method of  claim 1  wherein the organic aldehyde portion of the organic aldehyde adduct is aliphatic, alicyclic, aromatic, heterocyclic dialdehyde or mixtures thereof. 
     
     
         6 . The method of  claim 1  wherein the organic aldehyde portion of the organic aldehyde adduct is terephthalaldehyde or isophthalaldehyde. 
     
     
         7 . The method of  claim 1  wherein the organic compound being an organic tetraamine. 
     
     
         8 . The method of  claim 1  further comprising the step of:
 extruding the polybenzimidazole to a fiber or a film from the solution. 
 
     
     
         9 . The method of  claim 8  wherein for fiber spinning, the polybenzimidazole having an intrinsic viscosity of at least 0.50 dl/g. 
     
     
         10 . The method of  claim 8  wherein for fiber spinning, the solution having a % solids of the solution of at least 15%. 
     
     
         11 . The method of  claim 1  further comprising the step of:
 isolating the polybenzimidazole from the solvent. 
 
     
     
         12 . A method of making a polybenzimidazole comprising the steps of:
 reacting, in a solution,
 an organic compound having at least 4 amino groups with 
 an organic aldehyde adduct, the organic aldehyde adduct is a bisulfite salt. 
   
     
     
         13 . The method of  claim 12  wherein the reactants comprise at least 8% by weight of the solution. 
     
     
         14 . The method of  claim 12  where a solvent of the solution being selected from the group consisting of: N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), tetramethylene sulfone, and combinations thereof.