Patent ID: 8193255

Claim:
A process for the production of a part comprising an infusible polymer having elongated voids, the process comprising the steps: (a) providing particles of an infusible polymer, wherein the infusible polymer is selected from the group consisting of polyimides, poly(p-phenylenes), and polymers composed mostly or all of repeat groups of the formula wherein X is NH, N-Phenyl, O (oxygen) or S (sulfur), and Ar is p-phenylene, 4,4′ biphenylene or 1,4-naphthylylene; and (b) forming a mixture by mixing the particles of the infusible polymer with about 0.2 to about 10 volume percent of a second polymer, wherein said volume percentage is based on the total volume of said infusible polymer and said second polymer, and said second polymer is in the form of elongated pieces wherein a ratio of a longest dimension of said pieces to a smallest dimension of said pieces is at least 10:1 and said second polymer is one or more of polypropylene, polyethylene, an acrylic polymer, cellulose acetate, or a cellulosic polymer; (c) subjecting said mixture to pressure to form a part; and (d) heating said part to a temperature to burn off said second polymer; provided that said infusible polymer has a decomposition point above the temperature at which the second polymer is burned off.