Surface treatment of carbon microfibers

Abstract

A method of oxidizing the surface of carbon microfibers that includes contacting the microfibers with an oxidizing agent that includes sulfuric acid and potassiaum chlorate under reaction conditions sufficient to oxidize the surface. The invention also features a method of decreasing the length of carbon microfibers that includes contacting the microfibers with an oxidizing agent under reaction conditions sufficient to decrease the length.

1 . A method of oxidizing the surface of carbon microfibers comprising contacting said microfibers with an oxidizing agent that includes sulfuric acid and potassium chlorate under reaction conditions sufficient to oxidize said surface.  
     
     
         2 . A method of decreasing the length of carbon microfibers comprising contacting said microfibers with an oxidizing agent under reaction conditions sufficient to decrease said length by chopping said microfibers.  
     
     
         3 . The method of  claim 2  wherein said oxidizing agent comprises sulfuric acid and potassium chlorate.  
     
     
         4 . The method of  claim 1  or  2  wherein said oxidizing agent is in the liquid phase.  
     
     
         5 . The method of  claim 1  or  2  wherein the diameter of said microfibers is no greater than 1 micron.  
     
     
         6 . The method of  claim 1  or  2  wherein the diameter of said microfibers is no greater than 0.1 micron.  
     
     
         7 . The method of  claim 1  or  2  wherein the diameter of said microfibers in between 3.5 and 75 nanometers, inclusive.  
     
     
         8 . The method of  claim 1  or  2  wherein said microfibers comprise tubes having graphitic layers that are substantially parallel to the microfiber axis.  
     
     
         9 . The method of  claim 8  wherein said microfibers are substantially free of a continuous thermal carbon overcoat.  
     
     
         10 . A volume of carbon microfibers prepared according to the method of  claim 1  or  2 .  
     
     
         11 . A composite comprising the microfiber volume of  claim 10  in a matrix.  
     
     
         12 . The composite of  claim 11  wherein said matrix comprises an organic polymer.  
     
     
         13 . The composite of  claim 11  wherein said matrix comprises an inorganic polymer.  
     
     
         14 . The composite of  claim 11  wherein said matrix comprises a metal.  
     
     
         15 . The composite of  claim 11  wherein said matrix comprises a ceramic material.  
     
     
         16 . The composite of  claim 11  wherein said matrix comprises an elastomer.  
     
     
         17 . The microfiber volume of  claim 10  wherein said volume forms an adsorbent.  
     
     
         18 . The microfiber volume of  claim 10  wherein said volume forms a polymerization initiator.  
     
     
         19 . A volume of carbon fibrils comprising a multiplicity of fibrils having a morphology consisting of tubes that are free of a continuous thermal carbon overcoat and have graphitic layers that are substantially parallel to the fibril axis, 
 the outer surface of said graphitic layers having bonded thereto a plurality of oxygen-containing groups, or derivatives thereof.