The effect of the production method on the mechanical strength of an alumina porous hollow fiber

The mechanical strength of inorganic porous hollow fibers is an important property and is strongly affected by the production method. Three production methods for fibers are compared: non-solvent induced phase separation (NIPS), bio-ionic gelation with an internal multivalent ion source (BIG-I), and with an external ion source (BIG-E). The BIG-E fibers show insufficient mechanical integrity for strength analysis. Fibers prepared via BIG-I have a larger bending strength compared to fibers prepared using NIPS or BIG-E, combined with a larger scatter in their strength data. The large scatter likely originates from surface deformations present in the fiber wall, which can be reduced by further optimization of the production method. Statistical models are fitted to the measured strength data. The NIPS and BIG-I production methods yield fibers of which the strength distribution follows the Weibull model, presuming failure occurs at the weakest link.