Evaluation of the physical properties and filtration efficiency of PVDF/PAN nanofiber membranes by using dry milk protein

Abstract

In engineering applications, especially ultrafiltration (UF) applications, it is very important to use polyacrylonitrile (PAN) and poly (vinylidene fluoride) (PVDF) nanofiber membranes. In this study, membrane nanofibers made of pure PAN, PVDF: PAN blends, and pure PVDF (M1, M2, M3, M4, M5, and M6), were produced by the electrospinning technique with different contents of PVDF in each blend. The prepared membranes were characterized by field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), contact angle measurements, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectrophotometry, and differential scanning calorimetry-thermogravimetric analysis (DSC-TGA). In terms of the physical properties, the viscosity of the membranes increased with an increase in the content of PVDF in the blends compared with the viscosity of the pure polymer solutions. This led to increases in nanofiber diameter, pore size, and porosity by 261.664%, 875.107%, and 114.41%, respectively, when the content of PVDF increased from 20% (M2) to 80% (M5); this was also accompanied by an increase in the surface wettability of the membrane depending on its contact angle. In addition, the thermal properties and crystallinity of PAN improved after increasing the PVDF content from 20% (M2) to 60% (M4). Moreover, the filtration efficiency of the membranes was measured to determine the per cent reduction in pure water flux, reduction in mean depth (RMD) before and after using dry milk protein, the flux recovery ratio and porosity, giving values of 15.68%, 82.51%, 84.32%, and 67.79%, respectively, for the M4 membrane.

Studying the High Loading of Lead-Rubber Nanocomposites as Gamma Radiations Shielding.

“…The uniform distribution of lead nanoparticles enhances mechanical properties and contributes to the enhanced resistance of rubber models to gamma-ray shielding properties. The current study showed that increasing the concentration of lead nanoparticles increases the cutting distance and the nal force [32][33][34].…”

PVDF/Fe3O4@pDA@Ag Nanofiber Membranes with Multicore–Shell Structure for EMI Shielding

“…There were asymmetric stretching vibration bands at 836 and 1273 cm – 1 , and a bending vibration band associated with −CF 2 was identified at 475 cm – 1 . These peaks were identical to the chemical structure of PVDF. − In the spectra of PVDF/Fe 3 O 4 and PVDF/Fe 3 O 4 @pDA NFMs, the characteristic peak at 562 cm – 1 was assigned to Fe–O stretching in Fe 3 O 4 NPs. , Moreover, in the PVDF/Fe 3 O 4 @pDA spectrum, −NH bending vibration was detected near 1597 cm – 1 due to a large amount of −NH in pDA. , In the PVDF/Fe 3 O 4 @pDA@Ag spectrum, due to the complete coverage of the fiber surface by the Ag layer, only the Ag–O characteristic peak at 533 cm – 1 was detected …”

Preparation and Characterization of Superabsorbent Polymers (SAPs) Based on PUL-g- AM/AA by Microwave Irradiation

“…The percentage of increment in the pore volume was 263.78 % after adding 3 mM SDBS to the PUL-g-AM /AA; the results of pore volume (nm 3 ) and porosity % of SAPs are shown in Table 2. The pore volume of the hydrogel increased with SDBS compared to the pore volume of the hydrogel that did not contain SDBS [41].…”