A Wet-Spinning Fiber Process Providing Controlled Morphology of the Wet-Spun Fiber.
Patent Application, Filed 12 Mar 96,
DEPARTMENT OF THE NAVY WASHINGTON DC
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The present invention employs a fluorinated PI polyimide in a wet spinning fiber process. The fluorinated PI was chosen because of its desirable properties for electronic applications, and the present invention is not limited to this type of fiber. The solvent used for spinning of the fiber the solvent in the Spinning dope requires a material which can form solutions with the polyimide. Examples include ethyl acetate, methylene chloride, and dimethylacetamide DMAc. These solvents were chosen to reflect a large range of both solubility parameters and miscibility with water. For the coagulation bath utilized in the wet spinning process of the present invention, the coagulation baths range from 100 coagulant to 40 water which is equivalent to a mole fraction range between 1.0 and 0.2-0.3, with the lower limit dependent upon the non solvent used. The coagulant chosen was ethanol or methanol. The advantage of the present invention is that the internal morphology of the wet spun fibers can be controlled by varying the rate of polymer coagulation through adjustments in non-solventsolvent miscibility and precipitation strength of the coagulation bath.
- Solvents, Cleaners and Abrasives
- Manufacturing and Industrial Engineering and Control of Production Systems