Properties and characterization of Polyvinylide Fluoridepolytetrafluroethylene (PVDF-PTFE) membrane using N-Methyl-2-Pyrrolidone (NMP) and Dimethylacetamide (DMAc) as a solvent

Abstract

Membrane technology has gradually become a popular separation technology over the past few decades. There are significant advantages of using membranes for industrial processes such as no phase changes or chemical additives, easy to scale up, simple in operation and relatively low energy consumption. Present research shows polyvinylidene fluoride (PVDF) as one of the most used membrane materials. However, it is limited by a few problems which are fouling in water treatment, wetting in membrane contactors and limited at low temperature. Thus, by presence of polytetrafluoroethylene (PTFE) in the polymer that enhances hydrophobicity and reduces fouling problems. This research will concentrate on the several paramaters in the synthesis steps to achieve optimum condition of the membrane. The effect of polymer-solvent composition, different solvent, bath medium and evaporation time will affect the membrane’s morphology, including surface and cross-section morphology as well as porosity. Scanning electron microscopy (SEM) and fourier transform infrared (FTIR) analysis will be used to study the chemistry properties and membrane surface morphology. Besides, porosity test and water contact will be carried out to investigate the effect of membrane porosity and hydrophilic properties of membrane respectively. Also, single gas permeation test using nitrogen and carbon dioxide to study the efficiency of the membrane in permeability and selectivity to gas. The PVDF-PTFE membrane with 24% (w/w) with N-methyl-2-pyrrolidone (NMP) using 25% ethanol as coagulant bath without evaporation time has average pore size of membrane is 0.0168 m while the degree of porosity is 7.9129 m־¹. The membrane performed single gas permeation at low pressure which provides low permeability but high selectivity at about 1.58.