Characteristics of PVDF Membranes Irradiated by Electron Beam

Abstract

Polyvinylidene fluoride (PVDF) membranes were exposed vertically to a high energy electron beam (EB) in air, at room temperature. The chemical changes were examined by Fourier Transform Infrared Spectroscopy (FTIR). The surface morphologies were studied by Scanning Electron Microscopy (SEM) and showed some changes in the pore size. Thermogravimetric (TGA) analysis represented an increase in the thermal stability of PVDF due to irradiation. Electron paramagnetic resonance (EPR) showed the presence of free radicals in the irradiated PVDF. The effect of EB irradiation on the electrical properties of the membranes was analyzed in order to determine the dielectric constant, and an increase in the dielectric constant was found on increasing the dose. The surface hydrophilicity of the modified membrane was characterized by water contact angle measurement. The contact angle decreased compared to the original angle, indicating an improvement of surface hydrophilicity. Filtration results also showed that the pure water flux (PWF) of the modified membrane was lower than that of the unirradiated membrane.

Polydopamine‐coated poly(vinylidene fluoride) membranes with high ultraviolet resistance and antifouling properties for a photocatalytic membrane reactor

“…As shown in Figure (b), it was clear that the chemical structure of the pristine membrane was changed after 120 h of exposure to UV radiation. This change in the chemical structure was distinguished by a new sharp peak at a wave number of 1720 cm −1 , which appeared because of the stretching vibrations of the CC bond . Presumably, this CC bond appearing on the pristine PVDF UV‐irradiated membrane resulted from the abstraction of hydrogen atoms from the CH chain in the PVDF structure by UV‐induced free radicals .…”

“…37 Presumably, this C C bond appearing on the pristine PVDF UV-irradiated membrane resulted from the abstraction of hydrogen atoms from the C H chain in the PVDF structure by UV-induced free radicals. 37,38 Photon energy (hν) from UV light was strong enough to break the polymer chemical bonds and produced polymer free radicals. These generated free radicals reacted with oxygen to form peroxy radicals.…”

Electron beam irradiation of polyvinylidene fluoride/polyvinylpyrrolidone ultrafiltration membrane in presence of zwitterions molecules evaluation of filtration performances

“…The radiation dose of choice was 10 kGy, although a higher dose equals to 100 kGy was selected to study the effect of absorbed dose variation on the membrane's filtration performance. It is noted that the PVDF membrane can tolerate a very high EB irradiation dose of 1,000 kGy, so no membrane disintegration is expected [34]. EB irradiation of the membranes was performed with a pilot scale Van De Graaff electron beam accelerator (Vivirad France, 3 MeV, 0.5 mA, 43 cm scan width).…”

A Review on Catalytic Membranes Production and Applications

“…Jaleh et al [55] tested the irradiated PVDF by TGA to indicate the thermal stability of the membranes after grafting by irradiation step. The thermo-degradation of PVDF was observed at 420 o C, while after irradiation of PVDF the thermos degradation increased to 460 o C. The grafting of PVDF by irradiation improved the thermal stability of the catalytic membrane [55].…”