The preparation and study of poly(vinylidene fluoride)/ultrahigh-molecular-weight polyethylene/SiO2 hollow fiber membrane with network enhanced structure

The compatibility of poly(vinylidene fluoride) (PVDF)/ultrahigh-molecular-weight polyethylene (UHMWPE) blends is studied by methods of solubility parameter and melting temperature decreasing. And the melting behavior and crystallization properties are researched by rheological properties testing and differential scanning calorimetry. Based on these, PVDF/UHMWPE/SiO2 blends hollow fiber hydrophobic membranes with network enhanced structure and porous structure are prepared by thermally induced phase separation (TIPS) and screw extrusion spinning method, with mineral oil as diluent. Then the membrane morphology is observed by scanning electron microscopy (SEM). Finally, properties of membrane are studied by porosity and pore diameter analysis, stretching experiment and contact angle measurement. The results show that the porous structure is improved by interface pores formed due to the poor compatibility between PVDF and UHMWPE. Moreover, the network enhanced structure with rough surface is built by PVDF spherical micro-particles and SiO2 inorganic particles connected with UHMWPE micro-fibrils. The structure can strengthen mechanical properties of membrane.