Energy losses in ultrafiltration hollow fibers: Effect of shape

Mechanical and dielectric relaxation of ultrafiltration hollow fibers were studied by thermally stimulated creep and current, and differential scannin g calorimetry. The high sensitivity of thermally stimulated techniques show s 8 relaxations and/or transitions between -150 and 350 degrees C (degradat ion). Not all are related to the intrinsic nature of the material-indeed, 4 of them can be directly related to the shape of the membrane (porosity, di ameters, spinning conditions, etc.). Molecular mechanisms of these phenomen a are discussed. (C) 2000 John Wiley & Sons, Inc.