scholarly journals Solid–Liquid Europium Ion Extraction via Phosphonic Acid-Functionalized Polyvinylidene Fluoride Siloxanes

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1955 ◽  
Author(s):  
Mohammad Wehbi ◽  
Ahmad Mehdi ◽  
Ali Alaaeddine ◽  
Nada Jaber ◽  
Bruno Ameduri

Novel triethoxysilane and dimethyl phosphonate functional vinylidene fluoride (VDF)-containing terpolymers, for potential applications in Eu ion extraction from water, were produced by conventional radical terpolymerization of VDF with vinyltriethoxylsilane (VTEOS) and vinyldimethylphosphonate (VDMP). Although initial attempts for the copolymerization of VTEOS and VDMP failed, the successful terpolymerization was initiated by peroxide to lead to multiple poly(VDF-ter-VDMP-ter-VTEOS) terpolymers, that had different molar percentages of VDF (70–90 mol.%), VTEOS (5–20 mol.%) and VDMP (10 mol.%) in 50–80% yields. The obtained terpolymers were characterized by 1H, 19F, 29Si and 31P NMR spectroscopies. The crosslinking of such resulting poly(VDF-ter-VDMP-ter-VTEOS) terpolymers was achieved by hydrolysis and condensation (sol–gel process) of the triethoxysilane groups in acidic media, to obtain a 3D network, which was analyzed by solid state 29Si and 31P NMR spectroscopies, TGA and DSC. The thermal stability of the terpolymers was moderately high (up to 300 °C under air), whereas they display a slight increase in their crystallinity-rate from 9.7% to 12.1% after crosslinking. Finally, the dimethyl phosphonate functions were hydrolyzed into phosphonic acid successfully, and the europium ion extraction capacity of terpolymer was studied. The results demonstrated a very high removal capacity of Eu(III) ions from water, up to a total removal at low concentrations.

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3265 ◽  
Author(s):  
Li ◽  
Li ◽  
Li ◽  
Guan ◽  
Zheng ◽  
...  

A new synthesis method for organic–inorganic hybrid Poly(vinylidene fluoride)-SiO2 cation-change membranes (CEMs) is proposed. This method involves mixing tetraethyl orthosilicate (TEOS) and 3-mercapto-propyl-triethoxy-silane (MPTES) into a polyvinylidene fluoride (PVDF) sol-gel solution. The resulting slurry was used to prepare films, which were immersed in 0.01 M HCl, which caused hydrolysis and polycondensation between the MPTES and TEOS. The resulting Si-O-Si polymers chains intertwined and/or penetrated the PVDF skeleton, significantly improving the mechanical strength of the resulting hybrid PVDF-SiO2 CEMs. The -SH functional groups of MPTES oxidized to-SO3H, which contributed to the excellent permeability of these CEMs. The surface morphology, hybrid structure, oxidative stability, and physicochemical properties (IEC, water uptake, membrane resistance, membrane potential, transport number, and selective permittivity) of the CEMs obtained in this work were characterized using scanning electron microscope and Fourier transform infrared spectroscopy, as well as electrochemical testing. Tests to analyze the oxidative stability, water uptake, membrane potential, and selective permeability were also performed. Our organic–inorganic hybrid PVDF-SiO2 CEMs demonstrated higher oxidative stability and lower resistance than commercial Ionsep-HC-C membranes with a hydrocarbon structure. Thus, the synthesis method described in this work is very promising for the production of very efficient CEMs. In addition, the physical and electrochemical properties of the PVDF-SiO2 CEMs are comparable to the Ionsep-HC-C membranes. The electrolysis of the concentrated CoCl2 solution performed using PVDF-SiO2-6 and Ionsep-HC-C CEMs showed that at the same current density, Co2+ production, and current efficiency of the PVDF-SiO2-6 CEM membrane were slightly higher than those obtained using the Ionsep-HC-C membrane. Therefore, our novel membrane might be suitable for the recovery of cobalt from concentrated CoCl2 solutions.


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3585
Author(s):  
Xueqing Bi ◽  
Lujia Yang ◽  
Zhen Wang ◽  
Yanhu Zhan ◽  
Shuangshuang Wang ◽  
...  

Three-dimensional BaTiO3 (3D BT)/polyvinylidene fluoride (PVDF) composite dielectrics were fabricated by inversely introducing PVDF solution into a continuous 3D BT network, which was simply constructed via the sol-gel method using a cleanroom wiper as a template. The effect of the 3D BT microstructure and content on the dielectric and energy storage properties of the composites were explored. The results showed that 3D BT with a well-connected continuous network and moderate grain sizes could be easily obtained by calcining a barium source containing a wiper template at 1100 °C for 3 h. The as-fabricated 3D BT/PVDF composites with 21.1 wt% content of 3D BT (3DBT–2) exhibited the best comprehensive dielectric and energy storage performances. An enhanced dielectric constant of 25.3 at 100 Hz, which was 2.8 times higher than that of pure PVDF and 1.4 times superior to the conventional nano–BT/PVDF 25 wt% system, was achieved in addition with a low dielectric loss of 0.057 and a moderate dielectric breakdown strength of 73.8 kV·mm−1. In addition, the composite of 3DBT–2 exhibited the highest discharge energy density of 1.6 × 10−3 J·cm−3 under 3 kV·mm−1, which was nearly 4.5 times higher than that of neat PVDF.


Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5032
Author(s):  
Alec Ikei ◽  
James Wissman ◽  
Kaushik Sampath ◽  
Gregory Yesner ◽  
Syed N. Qadri

In the functional 3D-printing field, poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) has been shown to be a more promising choice of material over polyvinylidene fluoride (PVDF), due to its ability to be poled to a high level of piezoelectric performance without a large mechanical strain ratio. In this work, a novel presentation of in situ 3D printing and poling of PVDF-TrFE is shown with a d33 performance of up to 18 pC N−1, more than an order of magnitude larger than previously reported in situ poled polymer piezoelectrics. This finding paves the way forward for pressure sensors with much higher sensitivity and accuracy. In addition, the ability of in situ pole sensors to demonstrate different performance levels is shown in a fully 3D-printed five-element sensor array, accelerating and increasing the design space for complex sensing arrays. The in situ poled sample performance was compared to the performance of samples prepared through an ex situ corona poling process.


2021 ◽  
Author(s):  
Younes Ziat ◽  
Hamza Belkhanchi ◽  
Maryama Hammi ◽  
Charaf Laghlimi ◽  
A Moutcine

Abstract Recently, the rise of two dimensional amorphous nanostructured thin films have ignited a big interest because of their intriguingly isotropic structural and physical properties leading to potential applications in the nano-optoelectronics. However, according to literature, most of optoelectronic properties are investigated on chalcogenides related heterostructures. This has motivated the present work aiming to provide a new platform for the fabrication, examination of the properties and the applications of 2D nanostructured thin films based on epoxy/silicone blend. Thin films of Epoxy/Silicone loaded with nitrogen doped carbon nanotubes (N-CNTs) were prepared by sol-gel method and deposited on Indium Tin Oxide (ITO) glass substrates at room temperature. Further examination of optical properties aimed the investigation of optical pseudo-gap and Urbach energy and enabled the determination of processed films thickness based on Manifacier and Swanepol method. The results indicated that the unloaded thin films have a direct optical transition with a value of 3.61 eV followed by noticeable shift towards narrowing gaps depending on the loading rate. Urbach's energy is 0.19 eV for the unloaded thin films, and varies from 0.43 to 1.33 eV for the loaded thin films with increasing the rate of N-CNTs. It is inversely variable with the optical pseudo-gap. Finally, Epoxy/Silicone loaded with N-CNTs nanocomposites films can be developed as active layers with specific optical characteristics, giving the possibility to be used in electro-optical applications.


1998 ◽  
Vol 519 ◽  
Author(s):  
P.H. Mutin ◽  
C. Delenne ◽  
D. Medoukali ◽  
R. Corriu ◽  
A. Vioux

AbstractTransition metal oxide / phenylphosphonate hybrids with M/P ratios ranging from 1 to 5, (M= Ti, Zr) and metal phosphonates (M/P = 0.5) have been prepared by a sol-gel process involving in a first step the non-hydrolytic condensation between metal alkoxide and phosphonic acid leading to M-O-P bonds, followed by the hydrolysis-condensation of the remaining M-OR groups. The composition, texture and structure of the materials were investigated using EDX, TGA, XRD, IR and 31P NMR.


2020 ◽  
Vol 842 ◽  
pp. 63-68
Author(s):  
Xiao Zhang ◽  
Jian Zheng ◽  
Yong Qiang Du ◽  
Chun Ming Zhang

Three-dimensional (3D) network structure has been recognized as an efficient approach to enhance the mechanical and thermal conductive properties of polymeric composites. However, it has not been applied in energetic materials. In this work, a fluoropolymer based composite with vertically oriented and interconnected 3D graphite network was fabricated for polymer bonded explosives (PBXs). Here, the graphite and graphene oxide platelets were mixed, and self-assembled via rapid freezing and using crystallized ice as the template. The 3D structure was finally obtained by freezing-dry, and infiltrating with polymer. With the increasing of filler fraction and cooling rate, the thermal conductivity of the polymer composite was significantly improved to 2.15 W m-1 K-1 by 919% than that of pure polymer. Moreover, the mechanical properties, such as tensile strength and elastic modulus, were enhanced by 117% and 563%, respectively, when the highly ordered structure was embedded in the polymer. We attribute the increased thermal and mechanical properties to this 3D network, which is beneficial to the effective heat conduction and force transfer. This study supports a desirable way to fabricate the strong and thermal conductive fluoropolymer composites used for the high-performance polymer bonded explosives (PBXs).


2019 ◽  
Vol 43 (19) ◽  
pp. 7441-7456 ◽  
Author(s):  
P. E. Saranya ◽  
S. Selladurai

In the present study, pristine NiO- and Ce (0.5, 1.0, 1.5, and 2%)-doped NiO nanoflakes were synthesised using the sol–gel method for supercapacitor applications.


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