초록 |
In this study, microporous hollow fiber membranes were prepared by dry process. Dry process consists of three steps; first extrusion, second annealing and stretching. We spun hollow fiber precursors using semi crystalline polymer, like polypropylene (PP). The hollow fiber precursors were extruded through a single screw extruder equipped with tube-in-orifice structure spinneret. Hollow fiber precursor can be successfully obtained by controlled take-up speeds. The hollow fiber precursors were annealed in oven at 100, 120 and 140 ºC respectively. A sequential annealing process improved crystallinity. Stretching of annealed hollow fiber precursor was performed by various methods. Morphology of surface and cross section of membrane were measured by field emission scanning electron microscope (FE-SEM). The optimized preparation condition to prepare microporous hollow fiber membrane was confirmed through measurement of various take up speed, annealing and stretching condition. |