Study On Conditions Of Preparation Of IPP Hollow Fiber Membrane

Isotactic polypropylene is a kind of good membrane material which has good performances such as low price, large scale water treatment, insoluble at room temperature and so on. The iPP hollow fiber was prepared by the TIPS method in the research and the process conditions such as speed of the electromotor, pressure of the tank, temperature of the spinneret and N2 flux were inspected in order to prepare hollow fiber with well permeability, adjustable aperture, narrow pore size distribution , and high mechanical strength .The diversion cone was put into the spinneret in order to reduce the compression ratio of fluid in spinneret and reduce the entrance angle and make the fluid more stable; the air was be used as substitute for liquid coagulation bath in order to restrain the cortex; the N2 is used as substitute for water in order to make the process more easier.It can be found that the pore size, the porosity and the pure water flux of membrane ware all increased when the speed of the electromotor increased from2.53rpm to 3.53rpm, and the maximum of pure water flux and porosity of membrane were 1350L/(m2·h·bar) and 0.72. The mechanical strength of the membrane increased in the first and then decreased, and the maximum was 7.0Mpa when the speed of electromotor was 3.12Mpa; the pore size, the pure water flux and the porosity of membrane all increased as the pressure of tank increased from 0.075Mpa to 0.15Mpa; the mechanical strength of the membrane increased from 7.0Mpa to 9.0Mpa. When the temperature of spinneret increased from 145℃to 150℃, the dense cortex structure could be found on the external surface of the membrane, the pure water flux of the membrane decreased from 1789L/(m2·h·bar) to 625L/(m2·h·bar), but the mechanical strength increased from 4.1Mpa to 5.7Mpa. The wall thickness and diameter of the membrane reduced obviously as the N2 flux increased.The results showed that the increase of the electromotor speed and the pressure of the tank would promote the improvement of the pore size, the pure water flux and the porosity of membrane; the increase of the spinneret temperature would promote the development of the dense cortex structure, and then the pore size, the pure water flux and the porosity of membrane decreased.