Preparation and Characterization of PVDF‐HFP Membrane

Poly(vinylidene Fluoride-Hexafluoropropylene) Porous Membrane with Controllable Structure and Applications in Efficient Oil/Water Separation

Poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) porous membranes are fabricated via thermally induced phase separation (TIPS) with mixed diluent (dibutyl phthalate (DBP)/dioctyl phthalate (DOP)). The effects of mixed diluent are discussed in detail in term of morphology, mean pore size, selective wettability, etc. The results show that the membrane structure changes from spherulitic to bicontinuous with the change of DBP/DOP ratio. It is also found that the degree of crystallization decreases with the decrease of DBP/DOP ratio in mixed diluent. When liquid–liquid (L-L) phase separation precedes solid–liquid (S-L) phase separation, the obtained membranes have outstanding hydrophobicity and lipophilicity, excellent mechanical property. Additionally, the PVDF-HFP hybrid membranes are prepared with silica (SiO₂) particles and the effect of SiO₂ content on structure and properties is discussed. It is found that the PVDF-HFP hybrid membrane with 2 wt % SiO₂ (M3-S2) has better properties and higher filtration rate and separation efficiency for surfactant-stabilized water-in-oil emulsion separation. Moreover, the membrane M3-S2 also exhibits excellent antifouling performance for long-running.

A study on fabrication of PVDF-HFP/PTFE blend membranes with controllable and bicontinuous structure for highly effective water-in-oil emulsion separation

In this study, poly(vinylidene fluoride-co-hexafluropropylene) (PVDF-HFP)/polytetrafluoroethylene (PTFE) blend membranes for water-in-oil emulsion separation were prepared via a thermally induced phase separation (TIPS) method using dibutyl phthalate (DBP) and dioctyl phthalate (DOP) as a mixed diluent. The effects of PTFE content on the obtained membranes' structure and properties were studied. The results showed that the surface structure of the obtained membranes without addition of PTFE particles was denser and the surface pores got smaller. The porosity, pore size and hydrophobicity obviously increased with the increase in PTFE content. However, the breaking elongation and breaking strength decreased with the increase of PTFE content. When the PTFE content was 10 wt%, the obtained membrane showed the highest separation efficiency for different kinds of water-in-oil emulsions. In addition, the antifouling performance of the obtained membranes was also studied for many times of reuse. This paper introduces an effective and facile method to prepare hydrophobic–oleophilic membranes for water-in-oil emulsion separation.

PVDF-HFP/PTFE blend membranes were prepared for the first time via TIPS method with DBP and DOP as mixed diluent and PTFE as the blending polymer. The obtained membranes could separate different water-in-oil emulsions effectively.

Enhanced electroactive β-phase nucleation and dielectric properties of PVdF-HFP thin films influenced by montmorillonite and Ni(OH)2 nanoparticle modified montmorillonite

Enhancement of β-phase nucleation and dielectric properties of PVdF-HFP films due to incorporation of montmorillonite and Ni(OH)₂ nanoparticle modified montmorillonite.