| abstract |
The present invention relates to a process for creating a polymer film or coating. It includes the steps of: (a) creating a polymer solvent solution at an elevated temperature in excess of 65 degrees Centigrade by combining a polymer, especially a polymer containing a majority of polymer that is polyacrylonitrile, and most especially all polyacrylonitrile, and a solvent selected from the group consisting of dimethyl sulfoxide, dimethyl formamide, NaSCN, CaSCN, nitric acid, ethylene carbonate and mixtures thereof; (b) cooling the resulting solution to a temperature below 35 degrees Centigrade; (c) adding a nonsolvent liquid to said solution, said nonsolvent being selected from the group consisting of water, miscible liquid carbon compounds that do not dissolve said polymer, and combinations thereof: and (d) extracting said solvent and said nonsolvent from said solution to yield a solid polymer film. Preferably, the solution is created having an amount of at least 5%, by weight, of polymer, based on the total weight of the solution of polymer and solvent, and the solution is applied to a substrate before, during or after the cooling step to create a coating. |