The multi-pore-structure of polymer-silicon hollow fiber membranes fabricated via thermally induced phase separation combining with stretching

UHMWPE/PVDF/SiO2 hollow fiber membranes with a multi-pore structure were fabricated via thermally induced phase separation combining with stretching (TIPS-S). The preparation process utilized mineral oil as the diluent. A finite element calculation was used to predict generation of interface pores and the deformation of the polymer matrix. This approach enabled assumptions about phase separation and interface pore generation to be formulated. The formation and development of the interface pores were studied by scanning electron microscopy (SEM). Membrane performance was characterized by a variety of metrics including permeability, melting and crystallization behavior, porosity and pore diameter, and single-fiber tensile properties. The results indicated that the membrane evidenced a multi-pore-structure consisting of TIPS-generated pores, broken pores in the amorphous region, and interface pores formed by drawing. This complex pore structure enabled improved membrane permeability. These experimental results were in agreement with the assumptions obtained from the use of finite element analysis. (C) 2011 Elsevier B.V. All rights reserved.