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polyvinylidene-fluorides
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Synthesis and Characterization of PVDF Magnetic Nanocomposite
, M.Sc. Thesis Sharif University of Technology ; Forounchi, Massoud (Supervisor)
Abstract
PVDF (polyvinylidene fluoride) magnetic nanocomposite films were prepared by solution casting using two types of nanomagnetic particles: (i) magnetic nanoparticles synthesized by using an alkaline solution of mixed ferrous/ferric salts along with oleic acid as a coating agent at 70˚C; (ii) Fe3O4 nanoparticles prepared by hydrolysis of aqueous solution of ferrous/ferric salts with potassium hydroxide at room temprature. Scanning electron microscopy (SEM) showed that the PVDF magnetic nanocomposite had a porous structure with Fe3O4 nanoparticles dispersed inside the porous polymer matrix. The presence of crystalline magnetite within the polymer matrix was confirmed by X-Ray diffraction method...
Azo dye removal via surfactant-assisted polyvinylidene fluoride membrane
, Article Environmental Health Engineering and Management ; Volume 8, Issue 1 , 2021 , Pages 25-32 ; 24233765 (ISSN) ; Mousavi, A ; Bagheri Lotfabad, T ; Heydarinasab, A ; Yaghmaei, S ; Sharif University of Technology
Kerman University of Medical Sciences
2021
Abstract
Background: Recently, concerns have been raised regarding the environmental and public health safety of azo dyes, the most widely used synthetic dyes. The membrane technique has been introduced as one of the efficient methods for dye removal treatments. Polyvinylidene fluoride (PVDF) membrane manipulated by surfactants was studied for removal of the azo dye, carmoisine. Methods: PVDF membrane was prepared via non-solvent-induced phase separation (NIPS) and used to remove the azo dye, carmoisine. Three nonionic surfactants including Tween 20, Tween 60, and Tween 80 were used individually as additives in casting solutions to improve PVDF membrane properties. Results: Fourier-transform infrared...
PVDF Nano Composite Coatings Resistant to Ionizing Radiation
, M.Sc. Thesis Sharif University of Technology ; Forounchi, Massoud (Supervisor) ; Dadbin, Susan (Supervisor)
Abstract
Poly (vinylidene Fluoride) (PVDF)/organoclay nanocomposite films were prepared via melt mixing, solution casting and Co-precipitation techniques. The effects of different kinds of nanoclay, sample preparation techniques and electron beam irradiation on PVDF/Nanoclay nanocomposite are reported in this research project. Differential scanning calorimetry was used to study thermal properties and crystallinity of the PVDF and its nanocomposites. The chemical and crystalline structure of the samples was analysed by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) and the mechanical properties of the PVDF nanocomposite were characterized by stress strain test. The degree of...
Preparation and Characterization of Poly (lactic acid) - Poly (vinylidene fluoride) – Carbon Nanotubes Nano-composites
, M.Sc. Thesis Sharif University of Technology ; Frounchi, Masoud (Supervisor)
Abstract
Composite film PLA/PVDF and nanocomposite films PLA/PVDF/MWCNT with a solution method by solvent Dimethyl formamide was prepared at 65◦c. poly vinylidene fluoride as matrix phase and poly lacticacid was used an amplifier. In the next sextion multiwalled carbon nanotubes were added to the PLA/PVDF composite.Scaning Electron microscope results, showed that the PLA/PVDF composite and PLA/PVDF/MWCNT nanocomposites, non porous structure and carbon nanotubes in the polymer matrix have been well dispersed. The impact of nanoparticles in the polymer matrix by X-Ray Diffraction and Differential Scaning Calorimetry was investigated. With differential scaning calorimeter (DSC) and stress strain test,...
Preparation and Characterization of PVDF/ PVAc/ ND Nanocomposite
, M.Sc. Thesis Sharif University of Technology ; Frounchi, Masood (Supervisor)
Abstract
Polyvinylidene fluoride (PVDF) is remarkable since its mechanical properties, chemical stability and significant ferroelectricity. This Polymer has a simple chemical structure and can be found in five different crystal phases (α,β ,ɣ,δ and ε). Between these phases, beta shows a substantial pyro and piezoelectric activity since its great dipole moment. In this study PVDF/Poly(vinyl acetate)/Nanodiamond (ND) nanocomposite films were synthetized by solving in dimethylformamide adding ND particles to PVDF/PVAc blend in order to improve mechanical and piezoelectric properties. Scanning electron microscopy results showed that PVDF/PVAc are miscible and lead to a single crystal phase and dispersion...
Chemical Adjustment of Membrane Surface to Reduce Fouling in Membrane Bioreactors
, M.Sc. Thesis Sharif University of Technology ; Bastani, Dariush (Supervisor) ; Mousavi, Abbas (Supervisor)
Abstract
In this study, modification of Polyvinylidene fluoride membrane in order to reduce membrane fouling in membrane bioreactors is investiged. To achieve this goal, chemical modification and grafting methods were used. Initially, by chemical modification, the reaction was made to make hydroxyl groups on the membrane surface. The hydroxyl functional groups were used as a site for connecting of subsequent monomers. Finally, the lysozyme enzyme was used as the main modifier to improve the hydrophilicity and antibacterial properties of the membrane surface. To evaluate the performance of the modified membrane in comparison with the pristine membrane, different tests, such as water contact angle...
Preparation of Polyvinylidene Fuoride Membrane for Separation of Aroma Compounds in Apple Juice
, M.Sc. Thesis Sharif University of Technology ; Roosta Azad, Reza (Supervisor) ; Mousavi, Abbas (Co-Advisor)
Abstract
Many aroma compounds of fruit juice recovered by thermal evaporation and distillation processes can lead to undesirable chemical changes and even their loss. Pervaporation is a promising process for the recovery of volatile organic compounds from their aqueous solutions. In the present work, pervaporation recovery of Ethyl acetate as a model solution of apple juice’s aroma compound was evaluated with polyvinylidene fluoride (PVDF) and ethylvinylacetate (EVA) membranes. For PVDF and PES membranes in the feed concentration of 250-1000 ppm and the operating temperature of 30 ºC, separating factor , respectively, was obtained in the range of 67-70 and 49-53, and also total permeation flux was...
Preparation and Characterization of PVDF/PVAc/CNT Nanocomposites
, M.Sc. Thesis Sharif University of Technology ; Frounchi, Masoud (Supervisor)
Abstract
Many efforts have been performed on the poly(vinylidene fluoride), PVDF, due to its piezoelectric, pyroelectric and ferroelectric potentials. In this thesis Poly (vinyldene Flouride) (PVDF)/Poly (vinyl Asetate) (PVAc)/Multi-walled carbon nanotubes (MWCNT) and Poly (vinyldene Flouride) (PVDF)/Poly (vinyl Asetate) (PVAc)/Graphene Oxide nonasheets (GOn) nanocomposite films were prepared via solution casting method. The effect of concentration of PVAc, MWCNT and graphene oxide on PVDF nanocomposites were investigated. Graphene oxides synthesized by modified Hummer’s method. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results showed that the crystalline structure of...
Synthesis and Investigation of Physical Properties of PVDF/Graphene Nanostructured Membranes for Molecular Sieving
, M.Sc. Thesis Sharif University of Technology ; Esfandiar, Ali (Supervisor)
Abstract
Poly vinylidene fluoride (PVDF) as a fluorine polymer with acceptable thermal, chemical and physical property attractive create attention in membrane technology for water treatment application. However, with differential surface free energy between PVDF and water (∆G_s=30 mJ/m^2) PVDF polymer is divided as a hydrophobic materials, that is one of the basic problem for PVDF polymer. Due to its hydrophobicity the water molecules repulsion away from hydrophobic PVDF membrane surface as a spontaneous process with an entropy increasing and therefore pollutant molecules with hydrophobic functional group have tendency to adsorb onto membrane surface and dominate the boundary layer. In recent years...
High Saline Water Treatment by the Process of Membrane Distillation Combined with Solar Energy
, M.Sc. Thesis Sharif University of Technology ; Rajabi, Abbas (Supervisor) ; Musavi, Abbas (Supervisor)
Abstract
In this study, membrane distillation process was used for treatment of high salinity waters. The focus of this study is to simulate and build a setup of membrane distillation process. Since the membrane distillation process is based on the driving force of the temperature difference, the required temperature is provided by both the use of heaters and the use of solar energy. To increase the feed temperature by solar energy, a black polymer coating on the main membrane is used. The main membrane used in this process is PVDF polymer and the polymer coated on the surface is the PAN polymer. After simulating and constructing the laboratory setup, the influence of a variety of parameters on the...
Preparation and Modification of Lithium-ion Battery Membrane/Separator
, M.Sc. Thesis Sharif University of Technology ; Soltanieh, Mohammad (Supervisor) ; Mousavi, Abbas (Supervisor) ; Fathollahi, Abolfazl (Co-Supervisor)
Abstract
Electrolyte separator is the major component of lithium-ion batteries which the battery safety directly depends on it. In this work, a membrane separator based on the polyvinylidene fluoride (PVdF) was prepared via non-solvent induced phase separation (NIPS) method with water and ethanol as non-solvent and a mixture of dimethylformamide (DMF) and acetone as solvents. The effect of various acetone/DMF ratios and type of non-solvent on the structural, mechanical and electrochemical properties of separator was studied. The separator was characterized by FE-SEM, tensile strength, electrochemical AC-impedance spectroscopy, thermal stability and linear sweep voltammetry (LSV). Additionally, the...
Effect of synthesis method on magnetic and thermal properties of polyvinylidene fluoride/Fe3O4 nanocomposites
, Article Journal of Reinforced Plastics and Composites ; Volume 32, Issue 14 , 2013 , Pages 1044-1051 ; 07316844 (ISSN) ; Hadi, M ; Sharif University of Technology
2013
Abstract
Polyvinylidene fluoride magnetic nanocomposite films were prepared by solution casting using two types of magnetic nanoparticles: (a) magnetic nanoparticles synthesized by co-precipitation method using oleic acid as a coating agent and (b) Fe3O4 nanoparticles prepared by hydrolysis method without using a coating agent. Dynamic light scattering measurements showed mean diameters of 135 and 46 nm in co-precipitation and hydrolysis methods, respectively. Scanning electron microscopy showed that the magnetic nanoparticles were uniformly dispersed inside the polymer matrix. X-ray diffraction confirmed that Fe3O4 nanoparticles induced nucleation of β- crystalline phase in the matrix polymer. The...
Pharmaceuticals removal by immobilized laccase on polyvinylidene fluoride nanocomposite with multi-walled carbon nanotubes
, Article Chemosphere ; Volume 263 , 2021 ; 00456535 (ISSN) ; Golgoli, M ; Ghobadi Nejad, Z ; Sadeghzadeh, S ; Borghei, S. M ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
The presence of pharmaceutical micropollutants in water and wastewater is considered a serious environmental issue. To eliminate these pollutants, biodegradation of pharmaceuticals using enzymes such as laccase, is proposed as a green method. In this study, immobilized laccase was used for the removal of two model pharmaceutical compounds, carbamazepine and diclofenac. Polyvinylidene fluoride (PVDF) membrane modified with multi-walled carbon nanotubes (MWCNTs) were synthesized as a tailor-made support for enzyme immobilization. Covalently immobilized laccase from Trametes hirsuta exhibited remarkable activity and activity recovery of 4.47 U/cm2 and 38.31%, respectively. The results also...
Application of Membrane Bioreactors in Landfill Leachate Treatment
, M.Sc. Thesis Sharif University of Technology ; Khorashe, Farhad (Supervisor) ; Moosavi, Abbas (Supervisor) ; Kazemeyni, Mohammad (Supervisor)
Abstract
Treatment of landfill leachate with membrane bioreactor (MBR) in lab and pilot scale have been studied in this research. MBR biological adaptation procedure at start of biological treatment, choose of membrane materials, membrane production with highest treatment performance and lowest membrane foaling have been studied. Mixed liquor suspended solid of MBR at the start of adaptation period was 3000 ppm and at the end of this period became 7000 ppm, microbial community has been changed in this period. Number of microbial species were reduced and number of these adapted species were increased. Five membranes were prepared with different concentration of PVDF polymer, solvent and non-solvent to...
Removal of Pharmaceuticals from Polluted Water Using Carbon Nanotube-based Membranes Coated with Enzyme
, M.Sc. Thesis Sharif University of Technology ; Borghei, Mehdi (Supervisor) ; Ghobadi Nejad, Zahra (Co-Supervisor)
Abstract
Today, presence of micropollutants, including pharmaceutical compounds, in aquatic systems has turned into a major environmental challenge threatening the health of humans and many aquatic and terrestrial organisms. In the recent years, biodegradation of pharmaceuticals using enzymes, such as laccase, has been presented as a green method for eliminating these types of pollutants. Furthermore, regarding the improved stability and reusability of immobilized enzymes, these types of biocatalysts are suitable for industrial applications. Enzymatic membrane reactor is a promising method of enzymatic treatment and fabrication of a high-efficiency enzymatic membrane is a major step to begin this...
Investigation on Conductivity and Piezoelectric Effects on Biological Properties of Conductive Nerve Regenerating Scaffolds by Nano Composite of Gelatin/Polyvinyl Fluoride/Graphene
, M.Sc. Thesis Sharif University of Technology ; Ramazani Saadat Abadi, Ahmad (Supervisor) ; Bakhshandeh Abkenar, Haleh (Supervisor) ; Atyabi, Mohammad (Co-Supervisor)
Abstract
Neural system in human body due to limitated cell proliferation requires high care, because the damage causes serious hurts and disables different tissues. Limit regeneration in central neural system can cause different neural diseases including brain exhaustions specially in old people, but the peripheral neural system may have been disabled and intrupt some other tissue beacuase of possible external injuries before aging. So that while some damages like neural fibers severing, some new medical care methods are required. Some of these methods are outograft, allograft and xenograft which implants neural tissues either between other patient's tissues or from somebody else's; however these...
Design and Development of Multi-Sensor Array for Structural Health Monitoring of Pipelines
, M.Sc. Thesis Sharif University of Technology ; Zabihollah, Abolghasem (Supervisor)
Abstract
Structural Health Monitoring (SHM) of pipelines is an important task for economic/safety reasons which depends on the method of study of the integrity profile of the pipeline structure. Process pipes, particularly, pipelines in thermal power plants are susceptible to stress corrosion cracking (SCC). Failure of these pipes may result in catastrophic damages, thus, require systematic regular inspections. The damage assessment may demand embedding of appropriate sensors and specific data analysis techniques. According to what is reported from the respective experiments, data analysis of a single sensor may not be adequate to provide a reasonable damage assessment, and in turn to making a...
PVDF/SiO2 Nanocomposite Coating with Different Wettability in Contact with Oil and Water for phase Separation Propose
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor)
Abstract
increased cohesion up to 4H pencil. Results of immersion test in water showed stability of coatings. Polarization test in naphtha and water mixture for stainless steel, copper and aluminum meshes demonstrated 98.89%, 86.25% and 66.6% protection efficiency respectively. In order to study of oil and water separation efficiency, mixtures of water and naphtha with different content of naphtha were used. Separation test for 200μm St.St mesh in different slopes demonstrated that changing of slop increase separation efficiency up to 95.5% for water and up to 100% for naphtha. Separation test for meshes with different pore size demonstrated that meshes with small pore size are more appropriate for...
Preparation of PVDF/PMMA/PZT Nanocomposites and Studying of Its Crystal Structure, Morphology and Electrical Properties
, M.Sc. Thesis Sharif University of Technology ; Frounchi, Masoud (Supervisor)
Abstract
Polyvinylidene fluoride is highly regarded by researchers due to its piezoelectric properties, mechanical properties, chemical and thermal stability and biocompatibility. This thermoplastic polymer has a semi-crystalline structure and, depending on the crystallization conditions, has five distinct crystalline phases α, β, γ, δ and ε. The β, γ and δ phases are electroactive, and among them, the β phase has high piezoelectric activity due to its high dipole moment. This study focuses on increasing the amount of β phase in polyvinylidene fluoride and increasing its piezoelectric property. Polyvinylidene fluoride is highly miscible with oxygen containing polymers such as polymethyl...
Surface Modification of UF Membrane by Cationic Polymers
, M.Sc. Thesis Sharif University of Technology ; Mousavi, Abbas (Supervisor)
Abstract
One of the most efficient and effective methods of water and wastewater treatment is the use of membranes and can be a good alternative to traditional methods such as adsorption, chemical coagulation and .... One of the limitations of this method is membrane fouling, which limits its use in industry.In this study, ultrafiltration membrane made by phase inversion method from a combination of PVDF and SPES polymers and surface modified with hyperbranched polyethylene imine and its performance in cationic coating paint purification was investigated. Also, the performance of this membrane has been investigated by calculating the separation rate, pure water flux, contact angle and specifications...