Preparation Of High Density Polyethylene Hollow Fiber Membrane Via Thermally Induced Phase Separation

The thermally induced phase separation (TIPS) is one of the most versatile and widely utilized methods to produce a variety of microporous membranes. In this dissertation, high density polyethylene (HDPE) hollow fiber microporous membranes were fabricated via thermally induced phase separation method. The cloud point curves of HDPE-LP and HDPE-D/SO systems were measured with optical microscopy method, respectively. The torque behaviors of two systems were examed by using Haake rheometer. Dynamic phase diagrams for these two systems were determined according to the correlation between torque and temperature. Furthermore, their rheological properties were studied by using capillary rheometer. The factors which influence on the geometry structures of nascent HDPE hollow fiber were examined, such as polymer concentration, extrusion rate, nitrogen pressure and take-up speed, etc. Furthermore, parameteres which influence on the morphologies and performances of resulted membranes were investigated, for instance, the diluents, polymer content, spinning temperature, drawing ratio, extractants and extranted method, air gas distance and heat treatment etc. Finally, optimized conditions for membrane fabrication were summerized.