Porous polybenzimidazole resin and method of making same

Abstract

A porous polybenzimidazole (PBI) particulate resin is disclosed. This resin is easily dissolved at ambient temperatures and pressures. The resin is made by: dissolving a virgin PBI resin in a highly polar solvent; precipitating the dissolved PBI in a bath; and drying the precipitated PBI, the dried precipitated PBI being porous. The porous PBI resin may be dissolved by: mixing a porous PBI resin with a highly polar solvent at ambient temperatures and pressures to form a solution.

1 . A polybenzimidazole resin comprising:
 a porous polybenzimidazole (PBI) particulate.   
     
     
         2 . The polybenzimidazole resin of  claim 1  wherein said particulate having an average particle size of less than 500 micron (μm). 
     
     
         3 . The polybenzimidazole resin of  claim 1  wherein said particulate having an average particle size in the range of 50-500 micron (μm). 
     
     
         4 . The polybenzimidazole resin of  claim 1  wherein said particulate having an average particle size in the range of 100-400 micron (μm). 
     
     
         5 . The polybenzimidazole resin of  claim 1  wherein said porous particulate having a plurality of pores with diameters of less than 3.0 micron (μm). 
     
     
         6 . The polybenzimidazole resin of  claim 1  wherein said porous particulate having a plurality of pores with diameters in the range of 0.01-3.0 micron (μm). 
     
     
         7 . The polybenzimidazole resin of  claim 1  wherein said porous particulate having a plurality of pores with diameters in the range of 0.1-2.5 micron (μm). 
     
     
         8 . The polybenzimidazole resin of  claim 1  wherein said resin having an apparent density (g/cc) of less than 0.20. 
     
     
         9 . The polybenzimidazole resin of  claim 1  wherein said resin having an apparent density (g/cc) in the range of 0.01-0.20. 
     
     
         10 . The polybenzimidazole resin of  claim 1  wherein said resin having an apparent density (g/cc) in the range of 0.03-0.15. 
     
     
         11 . A method for making a porous polybenzimidazole resin comprising the steps of:
 dissolving a virgin PBI resin in a highly polar solvent;   precipitating the dissolved PBI in a bath; and   drying the precipitated PBI resin, the dried precipitated PBI resin being porous.   
     
     
         12 . The method of  claim 11  wherein virgin polybenzimidazole resin refers to sieved resin from the reactor. 
     
     
         13 . The method of  claim 11  wherein the highly polar solvent being selected from the group consisting of N—N-dimethyl acetamide (DMAc), dimethylsulfoxide (DMSO), N—N-dimethylformamide (DMF), N-methyl-2-pyrrolidine (NMP), pyridine, and combinations thereof. 
     
     
         14 . The method of  claim 11  wherein said bath comprising non-solvent for PBI resin. 
     
     
         15 . The method of  claim 14  wherein the non-solvent for the PBI resin includes water, methanol, and combinations thereof. 
     
     
         16 . The method of  claim 11  wherein precipitating being conducted at a temperature in the range of 50-90° C. 
     
     
         17 . The method of  claim 11  wherein precipitating being conducted at a temperature in the range of 60-80° C. 
     
     
         18 . The method of  claim 11  wherein the bath being agitated. 
     
     
         19 . The method of  claim 11  further comprising filtering the solution prior to precipitating. 
     
     
         20 . The method of  claim 19  wherein filtering further comprises filtering through a filter having a mesh size of 25 microns or less. 
     
     
         21 . The method of  claim 11  further comprising separating the precipitated polybenzimidazole resin from the bath. 
     
     
         22 . A method of making a polybenzimidazole solution comprising the steps of:
 mixing a porous polybenzimidazole (PBI) resin with a highly polar solvent at ambient temperatures and pressures.   
     
     
         23 . The method of  claim 22  wherein the highly polar solvent being selected from the group consisting of N—N-dimethyl acetamide (DMAc), dimethylsulfoxide (DMSO), N—N-dimethylformamide (DMF), N-methyl-2-pyrrolidine (NMP), pyridine, and combinations thereof.