Jj. Kim et al., STRUCTURAL STUDY OF MICROPOROUS POLYPROPYLENE HOLLOW-FIBER MEMBRANES MADE BY THE MELT-SPINNING AND COLD-STRETCHING METHOD, Journal of membrane science, 93(3), 1994, pp. 209-215
Microporous polypropylene hollow fiber membranes were prepared by the
melt-spinning and cold-stretching method. Factors affecting the membra
ne structure were melt-draw ratio, spinning temperature, and annealing
temperature. The degree of molecular orientation was affected by the
melt-draw ratio and spinning temperature, and the crystallinity of the
hollow fiber depended on the melt-draw ratio and annealing temperatur
e. Quantitative analyses of microporous membrane structure were perfor
med by image analysis, bubble point pressure measurement, and mercury
porosimetry. The porosity at the surface is smaller than that of the w
hole membrane. Wetting of the medium and shading in the image brought
about the differences in pore size determination by each method.