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vinyl-acetates
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Composites of carbon nanotubes with the blend of poly(vinylidene fluoride)/poly(vinyl acetate)
, Article Polymer (Korea) ; Volume 40, Issue 2 , 2016 , Pages 232-237 ; 0379153X (ISSN) ; Frounchi, M ; Sharif University of Technology
Polymer Society of Korea
2016
Abstract
Poly(vinylidene fluoride)/poly(vinyl acetate)/carbon nanotubes, PVDF/PVAc/CNT, composite films were prepared at various compositions via a solution casting method. The amorphous PVAc formed a miscible blend with PVDF and drastically improved dispersion of CNT in PVDF/CNT composites. Combination of ductile PVAc and rigid CNT had favorable effects on mechanical properties of PVDF. The elongation of PVDF increased from 8% to 300% with addition of 40 wt% PVAc and 0.5 wt% CNT and the modulus at 1.5 wt% CNT was almost 2.3 fold of that of the neat PVDF while retaining high ductility and tensile strength. XRD and FTIR results showed that CNT favored formation of β-crys-talline phase in PVDF. Also...
Study of gas separation properties of ethylene vinyl acetate (EVA) copolymer membranes prepared via phase inversion method
, Article Separation and Purification Technology ; Volume 62, Issue 3 , 22 September , 2008 , Pages 642-647 ; 13835866 (ISSN) ; Sadeghi, M ; Motamed Hashemi, M. M. Y ; Pourafshari Chenar, M ; Roosta Azad, R ; Sadeghi, M ; Sharif University of Technology
2008
Abstract
The gas separation properties of ethylene vinyl acetate (EVA) membranes containing 18 and 28 wt% of vinyl acetate (VA) were investigated in this study. The effects of membrane preparation conditions, such as thermal and thermal/wet phase inversion, and the type of solvent on the gas separation properties of EVA membranes were investigated. The permeation of pure O2, N2, CH4, and CO2 gases at different feed pressures ranging from 2 to 11 bar were examined. The results indicated that the CO2 permeability was evidently higher than those of the other gases. Furthermore, the solubility mechanism was found to be the dominant mechanism for permeation of gases through EVA membranes. Moreover, the...
Gas permeability measurement in polyethylene and its copolymer films
, Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) ; Razavi, J ; Mousavi, A ; Sharif University of Technology
2006
Abstract
In this research, low density polyethylene (LDPE) and poly ethylene-co-vinyl acetate (EVA) were used as polymeric materials. The methods used to produce LDPE and EVA was Film Blowing and ThermalDry Phase Inversion. The amount of permeability, diffusivity and solubility of O2 and CO2 through above polymers were obtained and also the effect of temperature, pressure and film thickness for LDPE was measured. The Barometric method was considered and measurements were based on ASTM standard. To study film cross-section morphology in EVA, Scanning Electron Microscopy (SEM) was applied. From results we considered that the amount of permeability and solubility were decreased by increasing film...
Effect of ethylene-vinyl acetate copolymer on the rheological behaviour of alumino-silicate/polyethylene wax suspensions
, Article Ceramics International ; Volume 28, Issue 5 , 2002 , Pages 507-514 ; 02728842 (ISSN) ; Taheri Nassaj, E ; Davami, P ; Sharif University of Technology
2002
Abstract
Ceramic suspensions were prepared from an alumino-silicate powder, polyethylene wax (PE-wax) as binder with additions of stearic acid (SA). The ceramic powder consisted of mullite, corundum and tridymite phases. The organic binders contained 3 to 8 wt.% ethylene-vinyl acetate (EVA) and were filled with various volume fractions of ceramic powder. The yield stresses of suspensions were estimated using shear stress-shear rate data measured at 90-120 °C. The addition level of EVA was shown to have a considerable effect on the yield stress of suspensions. The effect of EVA on the flow parameters was also investigated over the temperature range of 90 to 120 °C. It was shown that the addition of 5...
Poly (Lactic Acid)/Poly(Ethylene-Co-Vinyl Acetate) Nano-Composites as Packaging Films
, M.Sc. Thesis Sharif University of Technology ; Frounchi, Masoud (Supervisor)
Abstract
The purpose of this project was to produce and examine the Poly(lactic acid)/poly(ethylene-co-vinyl acetate)/ nano-clay nanocomposite by solution casting that can be used for food packaging. In this study, it was observed that solvent evaporation at 4°C gives uniform films, without phase separation and free of voids, in a certain composition of polymers related to the rate of solvent evaporation.According to DMTA results Poly(lactic acid) and poly(ethylene-co-vinyl acetate) with 28% vinyl acetate, were compatible in less than 10% poly(ethylene-co-vinyl acetate) content in blend of them. Also, results of SEM tests showed that ethylene-co-vinyl acetate particle size in blends with 3 and 5...
Production of Poly (ethylen-co-vinyl acetate) and Nano Diamond Nanocomposite
, M.Sc. Thesis Sharif University of Technology ; Frounchi, Masoud (Supervisor) ; Mousavi, Abbas (Supervisor)
Abstract
Ethylene vinyl acetate copolymer produces flexible products and is compatible with many polymers and additives, the reason is that it has Vinyl group which is polar and Ethylene group which is nonpolar. In fact, it consists of two parts. One is a hard and semi-crystalline Polyethylene region and the other is soft, flexible, polar, and amorphous Vinyl Acetate. Improving the properties of this copolymer can broaden its application. For this purpose, Ethylene Vinyl Acetate with 18 and 28% Vinyl Acetate was used as a matrix and nano-alumina as reinforcement in this project. The spherical structure and chemicallu active surface, along with significant mechanical properties, suggeats Alumina...
Investigation of morphology and bioactive properties of composite coating of HA/vinyl acetate on pure titanium
, Article Materials Science and Engineering B: Solid-State Materials for Advanced Technology ; Volume 128, Issue 1-3 , 2006 , Pages 243-249 ; 09215107 (ISSN) ; Yousefpour, M ; Xiudong, Y ; Li, X ; Yang, B ; Wu, Y ; Chen, J ; Xingdong, Z ; Sharif University of Technology
2006
Abstract
Electrochemical co-deposition approach was expanded to prepare composite bio-ceramic coating of hydroxyapatite (HA)/polyvinyl acetate on the surface of titanium. The role is to improve the bioactive and crystallization properties. The results of XRD, XPS, SEM and TEM characterization showed that by increasing amount of vinyl acetate in the composite bio-ceramic coating before and after immersing in the simulated body fluid (SBF), an oriented growth of HA planes on the (0 0 2) direction had been observed on titanium substrate. Also significant surface morphology changes were obtained
Preparation and Properties of Ethylene-vinyl Acetate/linear Low-density Polyethylene/Graphene Oxide Nanocomposite Films
, Article Polymer - Plastics Technology and Engineering ; Volume 54, Issue 11 , 2015 , Pages 1152-1158 ; 03602559 (ISSN) ; Ramazani, S. A ; Baniasadi, H ; Sharif University of Technology
Taylor and Francis Inc
2015
Abstract
Ethylene-vinyl acetate-based nanocomposites with 18 and 28 wt% vinyl acetate were prepared via solution casting method. To improve the mechanical and barrier properties of ethylene-vinyl acetate, linear low-density polyethylene, and graphene oxide were introduced to matrix. The morphological studies indicated that the graphene oxide diffraction peak disappeared in all prepared nanocomposites, probably due to its exfoliation; also proper dispersion and good interaction between nanofillers and polymer matrix were achieved. By introducing low amount of graphene oxide into the matrix, the mechanical and thermal properties and oxygen permeability were improved especially for those with 28 wt%...
Synthesis and characterization of novel 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo dodecane based nanopolymer-bonded explosives by microemulsion
, Article Journal of Molecular Liquids ; Volume 206 , June , 2015 , Pages 190-194 ; 01677322 (ISSN) ; Soleyman, R ; Zarandi, M ; Sharif University of Technology
Elsevier
2015
Abstract
2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo dodecane (CL-20)-based polymer/plastic bonded explosives are used in propellant formulation. It can be predicted that CL-20-based nano-polymer/plastic bonded explosives are able to have reduced composite sensitivity and superior mechanical strength. In the current study, we have prepared two kinds of CL-20-based nano-polymer/plastic bonded explosives with ethylene-vinyl acetate copolymer and glycidyl azide polymer via the microemulsion method. Several visual techniques such as SEM/AFM/TEM techniques have been utilized for complete characterization of CL-20-based...
Effects of preparation conditions on the morphology and gas permeation properties of polyethylene (PE) and ethylene vinyl acetate (EVA) films
, Article Chemical Engineering Research and Design ; Volume 88, Issue 12 , 2010 , Pages 1593-1598 ; 02638762 (ISSN) ; Gholizadeh, M ; Sedghi, S ; Pourafshari Chenar, M ; Ahmad Soltani, B ; Soltani, A ; Sharif University of Technology
2010
Abstract
In this study, the effect of film preparation conditions on the gas permeation properties of polyethylene (PE) and ethylene vinyl acetate (EVA) films (containing 18 and 28wt% vinyl acetate) was investigated. Film blowing and phase inversion methods were applied in the production of PE and EVA films, respectively. The permeation of pure oxygen and carbon dioxide gases was measured at room temperature. The results indicated that with the increase of PE film thickness, permeability and solubility of O2 and CO2 in these films decreased; but the diffusivities of gases through PE films increased. In addition, in the case of EVA copolymers, by increasing the content of vinyl acetate, the...
Investigation of barrier properties of poly(ethylene vinyl acetate)/organociay nanocomposite films prepared by phase inversion method
, Article Macromolecular Symposia ; Volume 274, Issue 1 , 2008 , Pages 1-5 ; 10221360 (ISSN) ; Ramazani, A ; Sharif University of Technology
2008
Abstract
In this research work, to reduce permeability of polyethylene vinyl acetate) packaging films, organoclay nanocomposites of these thermoplastics were prepared by solution method. Organoclay are mixed with polyethylene vinyl acetate (EVA) with 18 and 28% of vinyl acetate (VA) content in solution phase. Solutions of 3, 5 and 7% of organoclay are prepared under reflux condition and then nanocomposite films are prepared by thermal phase inversion method. Morphological and gas barrier properties of different prepared samples have been investigated. Morphology of prepared nanocomposite films and order of exfoliation of clay were investigated using X-ray diffraction (XRD) and transmission electron...
Properties of Radiation Induced LDPE/EVA Nanocomposits
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor) ; Sheikh, Nasrin (Supervisor)
Abstract
Polyethylene (PE) is used as an insulation material for wires and cables because of its excellent electrical properties. For such application, it can be exposed to the high energy irradiation such as gamma ray and electron beam (EB), making possible crosslinking of the PE. Most of the properties of PE are improved greatly after irradiation, but it was harden and split easily. Due to the flexibility of EVA, depending on the vinyl acetate content, it can improve the toughness of the LDPE significantly upon addition to this polymer. As a result, radiation induced LDPE/EVA blend has been a good candidate for the wire and cable insulation. Also, upon addition of a few amount of OC, different...
Effect of EVA, Nano-clay and Mixing Sequence on Physical and Mechanical Properties of High Density Polyethylene
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Reza (Supervisor)
Abstract
Blending different polymers to achieve a compound with modified Physical physical and mechanical properties, has interested researchers for years. Among all, LDPE and HDPE have attracted a great attention for this purpose; specially when a mineral filler like clay is another part of composite. In the related literature, it is proven that small amounts of clay can improve physical and mechanical properties in comparison to virgin blend. Focus of this research is on HDPE/EVA/Clay nanocomposite and its physical and mechanical properties. Having vinyl group, EVA is a compatibilizer that makes clay to disperse better; EVA can also makes the brittle HDPE tougher. At first, HDPE/EVA blend...
Adhesion and Viscoelestisity of EVA Hot Melt Adhesive
, M.Sc. Thesis Sharif University of Technology ; Frounchi, Masuod (Supervisor) ; Dadbin, Susan (Supervisor)
Abstract
A series of poly(ethylene-co-vinyl acetate) (EVA)-based hot melt adhesives containing either a raw rosin or a hydrogenated rosin ester have been prepared to investigate variation of viscosity, softening point and peel adhesion with composition. Adhesion of the prepared hot melt adhesive to the substrate was characterized by T-peel strength test. Increasing rosin had a prominent effect on the adhesion. Viscosity decreased and softening point increased as the wax content increased. Addition of zinc borate as a flame retardant decreased T-peel energy and increased the viscosity and softening point of the samples. Higher peeling strength accompanied with a good softening point and viscosity...
Rheological Characterization of Nanocomposite Alloy of Polyethylene/ Polyethylene Vinyl Acetate and Nano Cla
, M.Sc. Thesis Sharif University of Technology ; Ramazani Saadatanadi, Ahmad (Supervisor)
Abstract
In this thesis, polyethylene vinyl acetate and polyethylene shrinkable nanocomposite films with different percentages of an organoclay such as 0, 1, 3, 5 and 7% have been prepared via two-steps solution method. Morphological and properties of these films, including permeability and mechanical and rheological properties were investigated. Also the effect of addition of cross linking agent (DCP) was studied. Various tests including XRD, SEM, tensile and rheological properties were studied. XRD tests showed that the distance between a layer of or ganoclay increased to 32 percent. This indicates that the polymer chains between the layers of organoclay could be better. SEM examination showed that...
Gas barrier and mechanical properties of crosslinked ethylene vinyl acetate nanocomposites
, Article Journal of Composite Materials ; Volume 47, Issue 23 , 2013 , Pages 2987-2993 ; 00219983 (ISSN) ; Shafiee, M ; Abedsoltan, H ; Shafiee, A ; Sharif University of Technology
2013
Abstract
In this research, the effects of crosslinking agent and clay content on the morphology, barrier and mechanical properties of ethylene vinyl acetate-organoclay nanocomposites prepared by solution method were studied. Dicumyl peroxide has been used as crosslinking agent. The morphology of the prepared nanocomposites was investigated using wide-angle X-ray diffraction and transmission electron microscopy. Wide-angle X-ray diffraction and transmission electron microscopyindicated that the prepared nanocomposites had predominantly intercalated morphologies. The obtained results of permeability tests showed that the permeability of ethylene vinyl acetate films dramatically decreases with addition...
Preparation of ethylene vinyl acetate copolymer/graphene oxide nanocomposite films via solution casting method and determination of the mechanical properties
, Article Polymer - Plastics Technology and Engineering ; Volume 54, Issue 2 , Jan , 2015 , Pages 218-222 ; 03602559 (ISSN) ; Sedaghat, S ; Ramazani S. A, A ; Baniasadi, H ; Sharif University of Technology
Taylor and Francis Inc
2015
Abstract
Ethylene vinyl acetate/graphene oxide (EVA/GO) nanocomposite films were prepared via solution casting method. The morphological studies investigated using SEM and XRD methods and the results confirmed the formation of likely exfoliation structures and good interaction between matrix and fillers. The results of permeability measurements showed that films have good resistance against oxygen. Mechanical measurements revealed that Young’s modulus and tensile strength of EVA have improved with introducing GO because of proper dispersion of GO into matrix and good interaction between them; however, elongation at break decreased due to formation of strong and rigid polymer/filler network preventing...
Acrylamidevinyl acetate copolymer as a new UCST copolymer: Phase transition and aggregation behavior; an experimental and theoretical study
, Article Reactive and Functional Polymers ; Volume 181 , 2022 ; 13815148 (ISSN) ; Kordzadeh, A ; Saadatabadi, A. R ; Sharif University of Technology
Elsevier B.V
2022
Abstract
A high sensitive upper critical solution temperature (UCST) copolymer was synthesized through free radical copolymerization with acrylamide (AAm) and vinyl acetate (VA). The UCST behavior is due to a combination of hydrogen bonds and electrostatic potentials between copolymer chains. Turbidimetry, dynamic light scattering, and rheology studies were used to determine the phase transition and aggregation behavior. It is indicated that copolymer with 80% AAm has a phase transition temperature between 38 and 38.2 °C, which is suitable for releasing fever medicine. Also, the temperature gradient for the complete dissolution of the copolymer is 2 °C. The molecular dynamics simulations at a...
Improve the Rheological Behavior of Different Waxy Crude Oil by Using Variouse Additives
, M.Sc. Thesis Sharif University of Technology ; Ghotbi, Cyrus (Supervisor) ; Jafari Behbahani, Taraneh (Supervisor) ; Ramezani Saadatabadi, Ahmad (Co-Supervisor)
Abstract
Wax precipitation is one of the major problems in the transfer of crude oil from field production to refineries. This wax with asphaltene compounds and some water and solids, closes the oil pipeline. One of the ways to reduce the amount of wax in pipes is to use additives (flow improvers) to crude oil and improve its rheological behavior. In this research, Five Iranian crude oils were characterized with SARA test and then the effects of various additives including ethylene vinyl acetate (EVA) in concentrations of 500 and 1500 ppm, alkyl phenol ormaldehyde resins (NPFR) with 1500 ppm and styrene-(ethylene-cobutylene)- styrene (SEBS) with 1500 ppm on viscosity, wax appearance temperature...
EVA /BT/MWCNT Hybrid Composites: Morphology, Electrical and Mechanical Properties
, M.Sc. Thesis Sharif University of Technology ; Frounchi, Masoud (Supervisor)
Abstract
In this research, the EVA/BT/MWCNT nanocomposites were prepared via the solution casting method in the various weight fractions of Barium titanate (BT) and multi-walled carbon nanotubes (MWCNT). Barium titanate-based ceramic material has a high dielectric constant, and it is used in the manufacture of sensors, capacitors, and electrical memories. On the other hand, multi-walled carbon nanotubes, due to electric charges on their surface and high electrical conductivity, can affect the dielectric properties combined with barium titanate and the hybrid of these two materials a polymer matrix suitable for special applications. In this study, ethylene-vinyl acetate (EVA) copolymer was used as a...