Preparation of PVDF anionic exchange membrane by chemical grafting of GMA onto PVDF macromolecule

• A PVDF anionic exchange membrane is prepared successfully by chemically induced grafting PVDF macromolecule in solution.
• The PVDF anionic exchange membranes show low area resistance of 4.3 Ω . cm2 and high anionic permselectivity of 99%.
• The membranes show great thermal stability up to 171 ◦C and excellent alkali stability.
• This method is simple, low cost and environmentally friendly.

In this research, poly(vinylidene fluoride) (PVDF) anionic exchange membranes were prepared by a method of chemically induced grafting of glycidyl methacrylate (GMA) onto PVDF macromolecule in solution. Various preparation parameters, including initiator, monomer and cross-linker concentrations, grafting time and temperature, drying time of the anionic membranes, were established in correlation with area resistance and anionic permselectivity of the obtained anionic exchange membranes. The chemical and crystal changes of the membranes were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), respectively. Surface morphologies and thermal stability were also evaluated by field emission scanning electron microscopy (FT-SEM) and thermogravimetric analyzer (TGA). The results reveal that a PVDF anionic exchange membrane is successfully prepared by this method and shows excellent properties with area resistance as low as 4.3 Ω ⋅ cm2 and anionic permselectivity as high as 99%, which are comparable to those of some commercial anionic exchange membranes, such as AHA, AMX, AST and so on. The membranes are homogenous, compact and show great thermal stability up to 171 °C and excellent alkali stability.