溶胶黏度、氧化铝含量和旋转盘转速对凝胶纤维直径的影响

采用溶胶凝胶法制备多晶氧化铝纤维,在聚合氯化铝先驱体溶胶中加入5%的硅溶胶和一定的聚乙烯醇及表面活性剂等,真空浓缩制得具有可成纤性的溶胶;在高速旋转盘的离心力作用下甩制成纤维坯体。在固定其他工艺参数的条件下,讨论了在离心力成纤过程中溶胶的黏度、氧化铝含量和旋转盘的转速对凝胶纤维直径的影响。当溶胶内的氧化铝含量在24%左右,黏度为0.2～0.35 Pa.s时,溶胶呈现为牛顿型流体,具有较好的成纤性,制得的纤维坯体细而均匀;而对于黏度为0.35 Pa.s的溶胶,当旋转盘的旋转速率达到300 r/s时,凝胶纤维被再次细化,直径减小至4.4μm。

Influences of the Percentage Content of Alumina, Viscocity of Sol, and Rotating Speed of the Rotating Disk on the Diameter of Gelfiber

Polycrystalline alumina fibers are synthesized by sol-gel method.This method is to put 5% of silica sol,a certain amount of polyvinyl alcohol and surface active material into the precursor sol of polyaluminium chloride.Spinnable sol is prepared by vacuum concentration,and fiber preform is spinned from the sol by centrifugal force of the high speed rotating disk.The influences of theviscosity of sol,the percentage content of alumina,and the rotating speed of the rotating disk on the diameter of gelfiber are also discussed,while other technological parameters during the fiber forming process are same.When the percentage content of alumina and viscosity of sol respectively are 24% and 0.2～0.35 Pa.s,the sol appears as Newton fluid,has good spinnable nature,and the fiber preform is fine and uniform.But when viscosity of sol and rotating speed of the rotating disk to attain respectively are 0.35 Pa.s and 300 r/s,the diameter of gelfiber is reduced to 4.4 μm.