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    Role of different compatibilizing approaches on the microstructure and mechanical properties of polypropylene/talc composites

    , Article AIP Conference Proceedings ; Vol. 1593, issue , 15- 19 July , 2014 , pp. 428-431 ; ISSN: 0094243X Homayounfar, S. Z ; Bagheri, R ; Sharif University of Technology
    Abstract
    Since in a highly filled polymer, a major problem arises from non-uniformity of properties due to the poor dispersion of filler, the application of coupling agents have been directed to overcome this problem and also to enhance the mechanical performance of the composites by improving the adhesion at the interface. In this study, a comparison between two major coupling approaches is conducted: 1) Using PPgMA as a kind of compatibilizer which changes the nature of the matrix, 2) Using titanate coupling agent which takes action at the interface and reacts with hydroxyl groups at the inorganic filler surface, resulting in the formation of monomolecular layer on the inorganic surface to increase... 

    Effects of modified titanium dioxide nanoparticles on the thermal and mechanical properties of poly(l-lactide)-b-poly(ε-caprolactone)

    , Article Iranian Polymer Journal (English Edition) ; Volume 31, Issue 7 , 2022 , Pages 893-904 ; 10261265 (ISSN) Ebrahimi, H ; Sharif, F ; Ramazani, S. A. A ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2022
    Abstract
    Incorporating titanium dioxide (TiO2) nanoparticles into the polymeric matrix offers an opportunity to obtain nanocomposites with improved functionality. In this study, the commercial TiO2 nanoparticles (TNP) were surface treated by different concentrations of aminopropyl triethoxy silane (APTS) as a coupling agent and triethylamine (Et3N) as a surface grafting catalyst by an aqueous process to prepare a nanocomposite with superior properties. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were performed to confirm the successful surface modification of TNP. The prepared modified TiO2 nanoparticles (mTNP) with different weight fractions were used as... 

    Kondo lattice model at half-filling

    , Article Journal of Physics Condensed Matter ; Volume 20, Issue 25 , 2008 ; 09538984 (ISSN) Nourafkan, R ; Nafari, N ; Sharif University of Technology
    2008
    Abstract
    In this paper, we have studied the single-and two-channel Kondo lattice model consisting of localized spins interacting anti-ferromagnetically with itinerant electrons. We have employed the dynamical mean field theory and have used the exact diagonalization method in our impurity solver. This method allowed us to access low temperatures and large values of exchange couplings. Our results for the single-channel case confirm and extend the recent investigations. In the two-channel case, at absolute zero temperature for half-filling and for the exchange couplings J/t>0.8, we have found a spontaneous symmetry breaking quantum phase transition, with one band showing a metallic behavior and the... 

    Different types of electrospun nanofibers and their effect on microfluidic-based immunoassay

    , Article Polymers for Advanced Technologies ; Volume 30, Issue 4 , 2019 , Pages 973-982 ; 10427147 (ISSN) Mahmoudifard, M ; Vossoughi, M ; Soleimani, M ; Sharif University of Technology
    John Wiley and Sons Ltd  2019
    Abstract
    Protein capturing on polymeric substrate of microfluidic devices is a key factor for the fabrication of immunoassay with high sensitivity. In this work, simple and versatile technique of electrospinning was used to produce electrospun nanofibrous membranes (e.NFMs) with high surface area as a substrate for microfluidic-based immunoassay to increase sensitivity. It was found that the simultaneous use of e.NFM and 1-Ethylethyl-3-(3-dimethylaminopropyl)-carbodiimide/N-Hydroxysuccinimide hydroxysuccinimide as coupling agent has synergic effect on antigen immobilization onto the microchannels. It was found that the oxygen plasma technique for the creation of oxygen containing functional group... 

    Bioconjugation of interferon-alpha molecules to lysine-capped gold nanoparticles for further drug delivery applications

    , Article Journal of Dispersion Science and Technology ; Volume 29, Issue 8 , 2008 , Pages 1062-1065 ; 01932691 (ISSN) Ghorbani Aghdam, A ; Vossoughi, M ; Almzadeh, I ; Zeinali, M ; Sharif University of Technology
    2008
    Abstract
    Gold nanoparticles are potentially very attractive components for therapeutic delivery since they can be synthesized with any diameter from 1 to 200 nm to carry a payload of therapeutic molecules into a cell without triggering an immune response. Gold nanoparticles must undergo surface transformations before coupling to therapeutic molecules to become eligible for this purpose. It is now more understood that amine groups can bind to gold nanoparticles strongly, which has enabled surface modification of gold nanoparticles with amino acid lysine through its amine group. These lysine capped gold nanoparticles can further be coupled to therapeutic molecules for delivery purposes. In this study... 

    Dynamic stereochemistry of erigeroside by measurement of 1H-1H and 13C-1H coupling constants

    , Article Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy ; Volume 70, Issue 2 , 2008 , Pages 350-357 ; 13861425 (ISSN) Tafazzoli, M ; Ghiasi, M ; Moridi, M ; Sharif University of Technology
    2008
    Abstract
    Erigeroside was extracted from Satureja khuzistanica Jamzad (Marzeh Khuzistani in Persian, family of lamiaceae), and 1H, 13C, 13C{1H}, 1H-1H COSY, HMQC and J-HMBC were obtained to identify this compound and determine a complete set of J-coupling constants (1JC-H, 2JC-H, 3JC-H and 3JH-H) values within the exocyclic hydroxymethyl group (CH2OH) and anomeric center. In parallel, density functional theory (DFT) using B3LYP functional and split-valance 6-311++G** basis set has been used to optimized the structures and conformers of erigeroside. In all calculations solvent effects were considered using a polarized continuum (overlapping spheres) model (PCM). The dependencies of 1J, 2J and 3J... 

    Fabrication, characterization, and electrochemical performance of the hdpe/sepiolite nanocomposite as a novel separator for li-ion batteries

    , Article Express Polymer Letters ; Volume 15, Issue 11 , 2021 , Pages 1063-1080 ; 1788618X (ISSN) Mohammadzad, M. Kh ; Pircheraghi, G ; Sharifi, H ; Sharif University of Technology
    BME-PT and GTE  2021
    Abstract
    Separators are one of the most critically important components of lithium-ion batteries to ensure the safe performance of the battery. Commercial polyolefin separators have high thermal shrinkage and low electrolyte uptake, which confines the application of the battery. By using the thermally induced phase separation (TIPS) method, we successfully prepared HDPE/sepiolite nanocomposite separators with high thermal stability and electrolyte wettability. The sepiolite nanofibers are modified with the Vinyltriethoxysilane (VTES) as a coupling agent for better dispersion and interaction in the HDPE matrix. The purpose of fabricating this separator is to decrease the thermal shrinkage and... 

    Effectively exerting the reinforcement of polyvinyl alcohol nanocomposite hydrogel via poly(dopamine) functionalized graphene oxide

    , Article Composites Science and Technology ; Volume 217 , 2022 ; 02663538 (ISSN) Famkar, E ; Pircheraghi, G ; Nazockdast, H ; Sharif University of Technology
    Elsevier Ltd  2022
    Abstract
    Nature-inspired coating with polydopamine (PDA) is a promising way to improve the performance of graphene oxide (GO) based nanocomposites due to its high ability to enhance interactions in matrix-disperse systems. Here, we examined the capability of two types of PDA to develop the reinforced polyvinyl alcohol (PVA)/GO hydrogels. In the first mode, dopamine hydrochloride was polymerized as nanoparticles and then incorporated into PVA solution with GO nanoplatelets (P-NG hydrogel). In the second mode, polydopamine was polymerized in the presence of GO nanoparticles to obtain PDA surface-modified GO and then PVA nanocomposite hydrogel (P-CG sample). Rheological and tensile findings revealed... 

    Effect of pH, citrate treatment and silane-coupling agent concentration on the magnetic, structural and surface properties of functionalized silica-coated iron oxide nanocomposite particles

    , Article Physica E: Low-Dimensional Systems and Nanostructures ; Volume 44, Issue 3 , December , 2011 , Pages 618-627 ; 13869477 (ISSN) Mohammad Beigi, H ; Yaghmaei, S ; Roostaazad, R ; Bardania, H ; Arpanaei, A ; Sharif University of Technology
    Abstract
    Superparamagnetic iron oxide nanoparticles were synthesized by coprecipitation of iron chloride salts at various pH values (9, 10, 11 and12) that were adjusted using an ammonia solution. Increasing the pH from 9 to 12 led to decreases in the size of iron oxide nanoparticles from 7.9±1.4 to 5±0.6 nm and the saturation magnetization (M s) from 82.73 to 67.14 emu/g, respectively, when analyzed with transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). X-ray diffraction patterns as well as M s values showed that magnetite is the dominantly synthesized phase in the examined pH values. Unmodified iron oxide nanoparticles were coated with silica via the hydrolysis and... 

    Evaluation of biodiesel production using lipase immobilized on magnetic silica nanocomposite particles of various structures

    , Article Biochemical Engineering Journal ; Volume 79 , 2013 , Pages 267-273 ; 1369703X (ISSN) Kalantari, M ; Kazemeini, M ; Arpanaei, A ; Sharif University of Technology
    2013
    Abstract
    Nonporous and mesoporous silica-coated magnetite cluster nanocomposites particles were fabricated with various silica structures in order to develop a desired carrier for the lipase immobilization and subsequent biodiesel production. Lipase from Pseudomonas cepacia was covalently bound to the amino-functionalized particles using glutaraldehyde as a coupling agent. The hybrid systems that were obtained exhibited high stability and easy recovery regardless of the silica structure, following the application of an external magnetic field. The immobilized lipases were then used as the recoverable biocatalyst in a transesterification reaction to convert the soybean oil to biodiesel with methanol.... 

    Electrodeposition of long gold nanotubes in polycarbonate templates as highly sensitive 3D nanoelectrode ensembles

    , Article Electrochimica Acta ; Volume 75 , 2012 , Pages 157-163 ; 00134686 (ISSN) Bahari Mollamahalle, Y ; Ghorbani, M ; Dolati, A ; Sharif University of Technology
    Elsevier  2012
    Abstract
    Electrodeposition of long and well-defined gold nanotubes in polycarbonate (PC) templates is still a major concern due to pore blockage problems. In the present study, we introduce a novel method for electrodeposition of long gold nanotubes within the pores of PC templates for the first time. In order to deposit gold atoms onto the pore walls preferentially, pore walls were functionalized with a coupling agent. Short and thin Ni nanotubes were then electrodeposited at the bottom of the pores. Gold nanotubes were subsequently electrodeposited at constant potentials and low solution concentrations. The morphology of nanotubes was characterized by electron microscopy and their formation... 

    A simple route to synthesize zirconia antistatic thin films on glass substrates and their application to polymer-based composites

    , Article Materials Chemistry and Physics ; Volume 244 , 1 April , 2020 Naderi, A ; Dolati, A ; Afshar, A ; Palardy, G ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    In this study, zirconia antistatic coatings were synthesized by a simple dip coating sol-gel route on glass substrates, then applied to polymer-based composites to potentially improve their dust or water repellent capabilities. The coating solution contained a precursor (ZrCl4), solvent (isopropanol) and coupling agent. FTIR spectra confirmed ZrO2 and ZrO compounds in both solution and antistatic coating. FE-SEM images indicated ZrO2 fibers’ thickness was controlled by changing ZrCl4 concentration (150 g–15 g ZrCl4/l) or relative humidity (20%–60%) during coating drying. Fibers grew thicker when decreasing the former or increasing the latter. The surface electrical resistivity for all... 

    CO2/CH4 separation by mixed-matrix membranes holding functionalized NH2-MIL-101(Al) nanoparticles: Effect of amino-silane functionalization

    , Article Chemical Engineering Research and Design ; Volume 176 , 2021 , Pages 49-59 ; 02638762 (ISSN) Ahmadipouya, S ; Ahmadijokani, F ; Molavi, H ; Rezakazemi, M ; Arjmand, M ; Sharif University of Technology
    Institution of Chemical Engineers  2021
    Abstract
    In this study, NH2-MIL-101(Al) metal-organic frameworks (MOFs) covered with 3-aminopropyltriethoxysilane (APTES) were incorporated into the polyethersulfone (PES) to produce mixed-matrix membranes (MMMs) for CO2 separation. The APTES functionalization was performed to improve the MOF dispersion in the PES matrix. Different analyses such as X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and field emission scanning electron microscopy (FESEM) revealed that the MOFs surface successfully functionalized with APTES. An improvement in CO2/CH4 separation efficiency was observed in MMMs, and the performance... 

    CO2/CH4 separation by mixed-matrix membranes holding functionalized NH2-MIL-101(Al) nanoparticles: Effect of amino-silane functionalization

    , Article Chemical Engineering Research and Design ; Volume 176 , 2021 , Pages 49-59 ; 02638762 (ISSN) Ahmadipouya, S ; Ahmadijokani, F ; Molavi, H ; Rezakazemi, M ; Arjmand, M ; Sharif University of Technology
    Institution of Chemical Engineers  2021
    Abstract
    In this study, NH2-MIL-101(Al) metal-organic frameworks (MOFs) covered with 3-aminopropyltriethoxysilane (APTES) were incorporated into the polyethersulfone (PES) to produce mixed-matrix membranes (MMMs) for CO2 separation. The APTES functionalization was performed to improve the MOF dispersion in the PES matrix. Different analyses such as X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and field emission scanning electron microscopy (FESEM) revealed that the MOFs surface successfully functionalized with APTES. An improvement in CO2/CH4 separation efficiency was observed in MMMs, and the performance... 

    Efficient protein immobilization on polyethersolfone electrospun nanofibrous membrane via covalent binding for biosensing applications

    , Article Materials Science and Engineering C ; Volume 58 , 2016 , Pages 586-594 ; 09284931 (ISSN) Mahmoudifard, M ; Soudi, S ; Soleimani, M ; Hosseinzadeh, S ; Esmaeili, E ; Vossoughi, M ; Sharif University of Technology
    Elsevier Ltd  2016
    Abstract
    In this paper we introduce novel strategy for antibody immobilization using high surface area electrospun nanofibrous membrane based on ethyl-3-(3-dimethylaminopropyl)-carbodiimide/N-hydroxysuccinimide (EDC/NHS) coupling chemistry. To present the high performance of proposed biosensors, anti-staphylococcus enterotoxin B (anti-SEB) was used as a model to demonstrate the utility of our proposed system. Polymer solution of polyethersolfone was used to fabricate fine nanofibrous membrane. Moreover, industrial polyvinylidene fluoride membrane and conventional microtiter plate were also used to compare the efficiency of antibody immobilization. Scanning electron microscopy images were taken to...