Preparation and characterization of microporous polyethylene hollow fiber membranes

Microporous polyethylene (PE) hollow fiber membrane with a porosity of 43% and N2 permeation of 4.96 cm3 (STP)/cm2 s cmHg was prepared by melt‐spinning and cold‐stretching method. It was found that PE with a density higher than 0.96 g/cm3 should be used for the preparation of microporous PE hollow fiber membranes. By increasing the spin–draw ratio, both the porosity and the N2 permeation of the hollow fiber membranes increased. Annealing the nascent hollow fiber at 115°C for 2 h was suitable for attaining membranes with good performance. By straining the hollow fiber to higher extensions, the amount and size of the micropores in the hollow fiber wall increased, and the N2 permeation of the membranes increased accordingly.