SUSPENSION DRY SPINNING AND RHEOLOGICAL BEHAVIOR OF CERAMIC-POWDER-LOADED POLYMER-SOLUTIONS

Green ceramic fibers of Al2O3, Si3N4, Ce-ZrO2, and SiC were prepared b y suspension dry spinning of powder-loaded polymer solutions. The fibe r-forming polymer was ethyl methacrylate dissolved in methyl ethyl ket one. The experimental conditions for fiber formation were defined for the alumina system. Thread lengths measured as a function of extrusion rate showed a transition from capillary-limited fracture to continuou s fibers in agreement with Ziabicki's theory of thread formation. The conditions for spinnability were correlated to rheological parameters. Spinnable Al2O3 dopes were elastic fluids with a high viscosity (60 P a.s at 0.46 s-1) under the conditions of this study.