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    Improving the performance of cement-based composites containing superabsorbent polymers by utilization of nano-SiO2 particles

    , Article Materials and Design ; Volume 42 , 2012 , Pages 94-101 ; 02641275 (ISSN) Pourjavadi, A ; Fakoorpoor, S. M ; Khaloo, A ; Hosseini, P ; Sharif University of Technology
    2012
    Abstract
    The application of superabsorbent polymer (SAP) as an internal curing agent for cement based composites results in benefits such as reduced autogenous shrinkage and cracking. However, a reduction in compressive and flexural strength usually occurs due to the empty voids remained in the matrix after deswelling of SAP particles. Nanoparticles are good candidates for improving the mechanical performance of cementitious materials, due to their multiple mechanisms of action, not the least their high pozzolanic activity.In the present work, the capability of amorphous nano-SiO2 (NS) as the most widely used nanoparticle in cementitious materials, for retrieving mechanical properties of... 

    Synthesis and characterization of bioactive glass/forsterite nanocomposites for bone and dental implants

    , Article Ceramics - Silikaty ; Volume 56, Issue 4 , 2012 , Pages 331-340 ; 08625468 (ISSN) Kamalian, R ; Yazdanpanah, A ; Moztarzadeh, F ; Ravarian, R ; Moztarzadeh, Z ; Tahmasbi, M ; Mozafari, M ; Sharif University of Technology
    2012
    Abstract
    In this research, bioactive glass (BG) of the type CaO-P2O 5-SiO2 and nanocrystalline forsterite (NF) bioceramic were successfully synthesized via sol-gel processing method. Heat-treatment process was done to obtain phase-pure nanopowders. After characterization of each sample, the nanocomposite samples were prepared by cold pressing method and sintered at 1000°C. The samples were fully characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR) analyses. The average nanocrystallite size was determined using the Debye-Scherrer's formula 19.6 nm. The bioactivity was examined in vitro... 

    Sonochemical synthesis and measurement of optical properties of zinc sulfide quantum dots

    , Article Chemical Engineering Journal ; Volume 209 , 2012 , Pages 113-117 ; 13858947 (ISSN) Goharshadi, E. K ; Sajjadi, S. H ; Mehrkhah, R ; Nancarrow, P ; Sharif University of Technology
    2012
    Abstract
    A facile sonochemical method has been developed to prepare very small zinc sulfide nanoparticles (ZnS NPs) of extremely small size about 1. nm in diameter using a set of ionic liquids based on the bis (trifluoromethylsulfonyl) imide anion and different cations of 1-alkyl-3-methyl-imidazolium. The structural features and optical properties of the NPs were determined in depth with X-ray powder diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS) analysis, and UV-vis absorption spectroscopy. The energy band gap measurements of ZnS NPs were calculated by UV-vis absorption... 

    Tailoring of morphology and crystal structure of nanomaterials in MgO-TiO 2 system by controlling Mg:Ti molar ratio

    , Article Journal of Sol-Gel Science and Technology ; Volume 64, Issue 1 , October , 2012 , Pages 135-144 ; 09280707 (ISSN) Mohammadi, M. R ; Fray, D. J ; Sharif University of Technology
    Springer  2012
    Abstract
    The morphological manipulation and structural characterisation of TiO 2-MgO binary system by an aqueous particulate sol-gel route were reported. Different crystal structures including pure MgTiO 3, mixtures of MgTiO 3 and TiO 2 and mixtures of MgTiO 3 and Mg 2TiO 4 were tailored by controlling Mg:Ti molar ratio and annealing temperatures as the processing parameters. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) revealed that all compounds crystallised at the low temperature of 500 °C. Furthermore, it was found that the average crystallite size of the compounds depends upon the Mg:Ti molar ratio as well as the annealing temperature, being in the range 3-5 nm at... 

    Photoactive and self-cleaning TiO 2-SiO 2 thin films on 316L stainless steel

    , Article Thin Solid Films ; Volume 520, Issue 20 , 2012 , Pages 6355-6360 ; 00406090 (ISSN) Boroujeny, B. S ; Afshar, A ; Dolati, A ; Sharif University of Technology
    Abstract
    In this study, TiO 2-SiO 2 nanocomposite films with different amounts of SiO 2 were prepared by sol-gel process and were coated onto stainless steel 316L. The effect of addition of various amount of SiO 2 in the precursor solution on the photocatalysis, photo-generated hydrophilicity and self-cleaning property of TiO 2 thin films was investigated by X-ray diffraction, Fourier transform infrared spectroscopy, water contact angle measurements and UV spectroscopy. In the tested ranges of SiO 2 content and sintering temperature, the highest photocatalytic activity and self-cleaning property were observed in the 15 mol% SiO 2 sample sintered at 750 °C. Addition of less than 30 mol% SiO 2 had a... 

    Effect of low-frequency oxygen plasma on polysulfone membranes for CO 2/CH 4 Separation

    , Article Journal of Applied Polymer Science ; Volume 124, Issue SUPPL. 1 , 2012 , Pages E199-E204 ; 00218995 (ISSN) Modarresi, S ; Soltanieh, M ; Mousavi, S. A ; Shabani, I ; Sharif University of Technology
    2012
    Abstract
    Low-frequency O 2 plasma was used to modify the surface of polysulfone gas-separation membranes. The effects of the treatment time and plasma power input on the membranes were also investigated. Pure CO 2 and CH 4 gas-permeation measurements were performed before and after plasma treatment. The results show the increase of permeability of the treated membranes due to surface ablation and surface polarization up to 5.63 and 68.80 gas-permeation units for CH 4 and CO 2, respectively, whereas, the CO 2/CH 4 selectivity of the treated membranes varied from 7.7 to 45.3, depending on the treatment conditions. Attenuated total reflection-Fourier transform infrared spectroscopy determined the... 

    Synthesis and characterization of sol-gel derived hydroxyapatite-bioglass composite nanopowders for biomedical applications

    , Article Journal of Biomimetics, Biomaterials, and Tissue Engineering ; Volume 12, Issue 1 , 2012 , Pages 51-57 ; 16621018 (ISSN) Adibnia, S ; Nemati, A ; Fathi, M. H ; Baghshahi, S ; Sharif University of Technology
    2012
    Abstract
    The main purpose of this study is to prepare and characterize hydroxyapatite (HA)-10%wt bioglass (BG) composite nanopowders and its bioactivity. Composites of hydroxyapatite with synthesized bioglass are prepared at various temperatures. Suitable calcination temperature is chosen by evaluating of the phase composition. X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Scanning electron microscopy (SEM) techniques are utilized to characterize the prepared nanopowders. The bioactivity of the prepared composite samples is evaluated in an in vitro study by immersion of samples in simulated body fluid (SBF) for predicted time. Fourier transformed infrared (FTIR) spectroscopy and... 

    Ultrasonic-assisted synthesis of magnetite based MRI contrast agent using cysteine as the biocapping coating

    , Article Materials Chemistry and Physics ; Volume 131, Issue 1-2 , 2011 , Pages 170-177 ; 02540584 (ISSN) Ahmadi, R ; Malek, M ; Hosseini, H. R. M ; Shokrgozar, M. A ; Oghabian, M. A ; Masoudi, A ; Gu, N ; Zhang, Y ; Sharif University of Technology
    2011
    Abstract
    Magnetite nanoparticles (mean particle size ranging from 10 to 20 nm) were prepared by a biomoleculeassisted solution-phase approach under ultrasonic irradiation. Cysteine was used as the capping agent in the solution. The results show that cysteine could be an efficient biocapping agent in producing Fe3O4 nanoparticles. The crystal structure and magnetic properties of the nanoparticles were characterized by XRD and VSM techniques, respectively. FT-IR was used to investigate the presence of cysteine on the nanoparticles surface. The influence of pH value of the solution on the size distribution and hydrodynamic size of nanoparticles were studied by TEM and DLS methods, respectively. The MTT... 

    Photocatalytic activity of CuO nanoparticles incorporated in mesoporous structure prepared from bis(2-aminonicotinato) copper(II) microflakes

    , Article Transactions of Nonferrous Metals Society of China (English Edition) ; Volume 25, Issue 11 , November , 2015 , Pages 3634-3642 ; 10036326 (ISSN) Tadjarodi, A ; Akhavan, O ; Bijanzad, K ; Sharif University of Technology
    Nonferrous Metals Society of China  2015
    Abstract
    An easy method for preparing CuO nanoparticles incorporated in a mesoporous structure was presented based on the thermal decomposition of a copper complex. The novel copper coordination compound of [Cu(anic)2]·0.75H2O (anic= 2-aminonicotinate) with the microflake morphology was synthesized through the reaction of 2-aminonicotinic acid (Hanic) and copper(II) nitrate. Using elemental analysis and Fourier transform infrared (FTIR) spectroscopy, the chemical composition of CuC12H11.5N4O4.75 was proposed. Calcination process at 550 °C for 4 h transformed the microflakes into CuO nanoparticles incorporated in a mesoporous structure. The FTIR peaks assigned to 2-aminonicotinate were completely... 

    Hydrogel nanocomposite based on chitosan-g-acrylic acid and modified nanosilica with high adsorption capacity for heavy metal ion removal

    , Article Iranian Polymer Journal (English Edition) ; Volume 24, Issue 9 , September , 2015 , Pages 725-734 ; 10261265 (ISSN) Pourjavadi, A ; Mazaheri Tehrani, Z ; Salimi, H ; Banazadeh, A ; Abedini, N ; Sharif University of Technology
    Springer-Verlag London Ltd  2015
    Abstract
    In this study, a novel hybrid hydrogel based on chitosan, acrylic acid and amine-functionalized nanosilica was prepared and characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. This hydrogel nanocomposite was used for removal of Co2+, Cu2+, Pb2+ and Zn2+ ions from aqueous solution. The metal ion adsorption was measured by inductively coupled plasma mass spectrometry. The adsorption behavior showed that the presence of modified nanosilica enhanced the porosity of the hydrogel network and affected its adsorption capacity in response to different parameters such as nanosilica content, metal ion concentration, adsorbent content,... 

    Synthesis of Reduced Graphene Oxide-Carbon Nanotubes (rGO-CNT) Composite and Its Use As a Novel Catalyst Support for Hydro-Purification of Crude Terephthalic Acid

    , Article Industrial and Engineering Chemistry Research ; Volume 54, Issue 31 , 2015 , Pages 7591-7603 ; 08885885 (ISSN) Tourani, S ; Rashidi, A. M ; Safekordi, A. A ; Aghabozorg, H. R ; Khorasheh, F ; Sharif University of Technology
    American Chemical Society  2015
    Abstract
    Palladium nanocatalysts supported on reduced graphene oxide (rGO), multi walled carbon nanotubes (MWCNT), and rGO/CNT composite were synthesized by a wet impregnation method using PdCl2 as a precursor. Palladium loading was 0.3 wt %, and the catalysts were reduced at 300°C. The catalysts were characterized by inductively coupled plasma, Brunauer-Emmett-Teller (BET) analysis, Fourier transform infrared spectroscopy, X-ray powder diffraction, transmission electron microscopy, temperatue-programmed reduction, temperatue-programmed desorption, and Raman spectroscopy. The performance of the catalysts was investigated for hydro-purification of crude terephthalic acid (CTA) containing... 

    A facile particulate sol–gel route to synthesize nanostructured CoTiO3 thin films and powders and their characteristics

    , Article Journal of Materials Science: Materials in Electronics ; Volume 26, Issue 7 , July , 2015 , Pages 5243-5253 ; 09574522 (ISSN) Mohammadi, A ; Ghorbani, M ; Sharif University of Technology
    Springer New York LLC  2015
    Abstract
    Nanostructured CoTiO3 thin films and powders were prepared by a straightforward aqueous particulate sol–gel route. Titanium(IV) isopropoxide and cobalt chloride were used as titanium and cobalt precursors, respectively. Also, hydroxypropyl cellulose was used as a polymeric fugitive agent in order to increase the specific surface area. The effect of Co:Ti molar ratio and annealing temperature were studied on the crystallization behavior and chemical properties of the products. X-ray diffraction and Fourier transform infrared spectroscopy revealed that the powders crystallized at the low annealing temperature of 300 °C for 1 h, containing anatase-TiO2,... 

    Structural and optical properties of Fe and Zn substituted CuInS2 nanoparticles synthesized by a one-pot facile method

    , Article Journal of Materials Chemistry C ; Volume 3, Issue 4 , Nov , 2015 , Pages 889-898 ; 20507534 (ISSN) Vahidshad, Y ; Tahir, M. N ; Zad, A. I ; Mirkazemi, S. M ; Ghazemzadeh, R ; Tremel, W ; Sharif University of Technology
    Royal Society of Chemistry  2015
    Abstract
    We substitute indium present in the CuInS2 ternary compound by iron and zinc using a facile one-pot synthesis method. The quaternary compound of CuIn1-xMxS2 (M = Fe and Zn) was synthesized by dissolving CuCl, InCl3, FeCl3, Zn(ac)2 and SC(NH2)2 as precursors in 1-octadecene, oleylamine and oleic acid as non-coordinating, coordinating and capping agent solvents, respectively. Oleic acid, oleylamine and thiourea were used respectively as a hard Lewis base, borderline Lewis base (in comparison with oleic acid) and soft Lewis base to form appropriate complexes. The complex formation, structure, and... 

    Polyelectrolyte nanocomposite membranes using imidazole-functionalized nanosilica for fuel cell applications

    , Article Journal of Macromolecular Science, Part B: Physics ; Volume 54, Issue 1 , Nov , 2015 , Pages 17-31 ; 00222348 (ISSN) Tohidian, M ; Ghaffarian, S. R ; Nouri, M ; Jaafarnia, E ; Haghighi, A. H ; Sharif University of Technology
    Taylor and Francis Inc  2015
    Abstract
    The preparation and characterization of a new type of nanocomposite polyelectrolyte membrane, based on DuPont Nafion/imidazole-modified nanosilica (Im-Si), for direct methanol fuel cell applications is described. Related to the interactions between the protonated imidazole groups, grafted on the surface of nanosilica, and negatively charged sulfonic acid groups of Nafion, new electrostatic interactions can be formed in the interface of Nafion and Im-Si which result in both lower methanol permeability and also higher proton conductivity. Physical characteristics of these manufactured nanocomposite membranes were investigated by scanning electron microscopy, thermogravimetry analysis,... 

    Hydrothermally synthesized CuO powders for photocatalytic inactivation of bacteria

    , Article Acta Physica Polonica A ; Volume 127, Issue 6 , 2015 , Pages 1727-1731 ; 05874246 (ISSN) Azimirad, R ; Safa, S ; Akhavan, O ; Sharif University of Technology
    Abstract
    Various morphologies of monoclinic CuO powders were synthesized by hydrothermal treatment of copper nitrate, copper acetate or copper sulfate. The synthesized samples were characterized by scanning electron microscopy, X-ray diffractometry, the Fourier transform infrared spectroscopy, and diffuse reflectance spectrophotometry. Antibacterial activity of the samples was studied against Escherichia coli bacteria in dark and under visible light irradiation. Although the different precursors yielded the same band gap energies (≈1.6 eV) for the synthesized CuO samples, they resulted in various morphologies (hierarchy of stabilized micro/nanostructures), specific surface areas, concentrations of... 

    Corrosion protection of 1050 aluminium alloy using a smart self-cleaning TiO2-CNT coating

    , Article Surface and Coatings Technology ; Volume 275 , 2015 , Pages 224-231 ; 02578972 (ISSN) Shadravan, A ; Sadeghian, Z ; Nemati, A ; Mohammadi, S. P ; Sharif University of Technology
    Elsevier  2015
    Abstract
    Inclusion of carbon nanotubes (CNTs) into the titanium dioxide coating on 1050 aluminium alloy was studied with the aim at enhancing the corrosion resistance of the surface. Composite coatings with various contents of CNTs were prepared via the sol-gel method and dip coating. XRD and FTIR phase and structural evaluations showed the presence of anatase phase in all thin films. Concomitant enhanced corrosion behaviour in the presence of CNTs was resulted from polarization potentiodynamic test. Band-gap evaluation was performed using absorbance spectra of coatings and showed considerable decrease of band-gap energy in the presence of CNTs. Photocatalytic properties and hydrophilicity of... 

    Development of chitosan/bacterial cellulose composite films containing nanodiamonds as a potential flexible platform for wound dressing

    , Article Materials ; Volume 8, Issue 9 , 2015 , Pages 6401-6418 ; 19961944 (ISSN) Ostadhossein, F ; Mahmoudi, N ; Morales Cid, G ; Tamjid, E ; Navas Martos, F. J ; Soriano Cuadrado, B ; Paniza, J. M. L ; Simchi, A ; Sharif University of Technology
    MDPI AG  2015
    Abstract
    Chitosan/bacterial cellulose composite films containing diamond nanoparticles (NDs) with potential application as wound dressing are introduced. Microstructural studies show that NDs are uniformly dispersed in the matrix, although slight agglomeration at concentrations above 2 wt % is seen. Fourier transform infrared spectroscopy reveals formation of hydrogen bonds between NDs and the polymer matrix. X-ray diffraction analysis indicates reduced crystallinity of the polymer matrix in the presence of NDs. Approximately 3.5-fold increase in the elastic modulus of the composite film is obtained by the addition of 2 wt % NDs. The results of colorimetric analysis show that the composite films are... 

    Preparation of PVA nanocomposites using salep-reduced graphene oxide with enhanced mechanical and biological properties

    , Article RSC Advances ; Volume 5, Issue 112 , 2015 , Pages 92428-92437 ; 20462069 (ISSN) Pourjavadi, A ; Pourbadiei, B ; Doroudian, M ; Azari, S ; Sharif University of Technology
    Royal Society of Chemistry  2015
    Abstract
    Salep, known as a biodegradable polysaccharide, is hydrolyzed and used as both a reducing agent and stabilizer for graphene oxide (GO). The functionalized reduced graphene oxide (f-rGO) is homogenously dispersed in an aqueous solution of poly(vinyl alcohol) (PVA). PVA based hydrogel and film nanocomposites are prepared and proposed as new biomaterials for tissue engineering applications. The mechanical properties of the film nanocomposites are investigated with varying content of f-rGO, glycerol and citric acid as a reinforcing agent, a plasticizer agent and a cross linking agent respectively. For the first time, chemically cross linked PVA hydrogels are synthesized using... 

    Synthesis and application of diethanolamine-functionalized polystyrene as a new sorbent for the removal of p-toluenesulfonic acid from aqueous solution

    , Article Journal of Industrial and Engineering Chemistry ; Volume 30 , October , 2015 , Pages 281-288 ; 1226086X (ISSN) Davarpanah, M ; Ahmadpour, A ; Rohani Bastami, T ; Dabir, H ; Sharif University of Technology
    Korean Society of Industrial Engineering Chemistry  2015
    Abstract
    Polystyrene resin was functionalized by diethanolamine for the efficient removal of p-toluenesulfonic acid (p-TSA) from aqueous solution. Functionalized adsorbent (DEA-PS) was characterized by elemental analysis, Fourier transform infrared spectroscopy, point of zero charge measurement and field-emission scanning electron microscopy. According to the results, maximum removal of p-TSA was observed at the pH range of 2.5-5. The adsorption kinetics of p-TSA onto DEA-PS was represented by pseudo-first-order model and the equilibrium data followed Langmuir model well. The adsorption process was endothermic and spontaneous, along with the positive change of entropy. The regeneration of DEA-PS was... 

    Fabrication of MEA based on sulfonic acid functionalized carbon supported platinum nanoparticles for oxygen reduction reaction in PEMFCs

    , Article RSC Advances ; 2015 , Pages 85775-85784 ; 20462069 (ISSN) Gharibi, H ; Yasi, F ; Kazemeini, M ; Heydari, A ; Golmohammadi, F ; Sharif University of Technology
    Royal Society of Chemistry  2015
    Abstract
    The Nafion ionomer affects the efficiency of the platinum (Pt) catalyst by blocking the active sites thereby restricting the gas permeability of the catalyst layer; but, there is a limitation in the quantity of Nafion ionomer that needs to be added without affecting the cell performance. Sulfonation of carbon-supported catalysts as mixed electronic and protonic conductors has been reported to be an efficient way to increase the triple-phase boundaries. In order to improve the utilization and activity of cathodic catalysts in the oxygen reduction reaction (ORR), Pt nanoparticles were loaded on a mixture of Vulcan XC-72R and MWCNTs, which were functionalized in a mixture of 96% sulfuric acid...