Limits...
Characteristics of PVDF Membranes Irradiated by Electron Beam.

Jaleh B, Gavary N, Fakhri P, Muensit N, Taheri SM - Membranes (Basel) (2015)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Bu-Ali Sina University, Hamedan 65174, Iran. jaleh@basu.ac.ir.

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.

No MeSH data available.


(a) Fourier transform infrared spectroscopy (FTIR) spectra of irradiated and unirradiated Polyvinylidene fluoride (PVDF) membrane; and (b) absorbance at 1735 cm−1 (C=C) versus electron beam (EB) dose in terms of kGy.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4384087&req=5

membranes-05-00001-f001: (a) Fourier transform infrared spectroscopy (FTIR) spectra of irradiated and unirradiated Polyvinylidene fluoride (PVDF) membrane; and (b) absorbance at 1735 cm−1 (C=C) versus electron beam (EB) dose in terms of kGy.

Mentions: Figure 1a shows FTIR spectra of the unirradiated and irradiated PVDF membranes. In the unirradiated sample, two absorption band located at 2978 cm−1 and 3024 cm−1 correspond to the symmetric and asymmetric stretching vibration of the CH2 groups. The absorption region from1300 to 1000 cm−1 corresponds to fluorocarbon absorption. The band appearing at 1735 cm−1 is due to the C=C stretching vibration and the peak at 1828 cm−1 is assigned to the C=O (carbonyl) groups resulting from the formation of hydroperoxide radicals initiated by irradiation in air [11,15,16]. The spectra of the irradiated membrane did not show any major changes in the main absorption bands relative to those of the unirradiated sample. This result has been reported in other works before [8,9,10,11]. However, a difference was observed between unirradiated and irradiated samples that is shown in Figure 1b. This chart shows the transmittance at 1735 cm−1 as a function of dose. It illustrates by increasing the dose to 150 kGy the transmittance increases (it means that the intensity of the peak decreases) that is resulting from crosslinking, then the transmittance decreases as the irradiation dose goes higher, which can be attributed to the predomination of chain scission over crosslinking at higher doses (>150 kGy).


Characteristics of PVDF Membranes Irradiated by Electron Beam.

Jaleh B, Gavary N, Fakhri P, Muensit N, Taheri SM - Membranes (Basel) (2015)

(a) Fourier transform infrared spectroscopy (FTIR) spectra of irradiated and unirradiated Polyvinylidene fluoride (PVDF) membrane; and (b) absorbance at 1735 cm−1 (C=C) versus electron beam (EB) dose in terms of kGy.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4384087&req=5

membranes-05-00001-f001: (a) Fourier transform infrared spectroscopy (FTIR) spectra of irradiated and unirradiated Polyvinylidene fluoride (PVDF) membrane; and (b) absorbance at 1735 cm−1 (C=C) versus electron beam (EB) dose in terms of kGy.
Mentions: Figure 1a shows FTIR spectra of the unirradiated and irradiated PVDF membranes. In the unirradiated sample, two absorption band located at 2978 cm−1 and 3024 cm−1 correspond to the symmetric and asymmetric stretching vibration of the CH2 groups. The absorption region from1300 to 1000 cm−1 corresponds to fluorocarbon absorption. The band appearing at 1735 cm−1 is due to the C=C stretching vibration and the peak at 1828 cm−1 is assigned to the C=O (carbonyl) groups resulting from the formation of hydroperoxide radicals initiated by irradiation in air [11,15,16]. The spectra of the irradiated membrane did not show any major changes in the main absorption bands relative to those of the unirradiated sample. This result has been reported in other works before [8,9,10,11]. However, a difference was observed between unirradiated and irradiated samples that is shown in Figure 1b. This chart shows the transmittance at 1735 cm−1 as a function of dose. It illustrates by increasing the dose to 150 kGy the transmittance increases (it means that the intensity of the peak decreases) that is resulting from crosslinking, then the transmittance decreases as the irradiation dose goes higher, which can be attributed to the predomination of chain scission over crosslinking at higher doses (>150 kGy).

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, Bu-Ali Sina University, Hamedan 65174, Iran. jaleh@basu.ac.ir.

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.

No MeSH data available.