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Bābolsar, Iran

Mohammadi A.,University of Mazanadaran | Barikani M.,Iran Polymer And Petrochemical Institute
Materials Characterization

In this study, superparamagnetic thiodiglycol coated Fe3O 4 nanoparticles (TDG-Fe3O4) were synthesized using in situ coprecipitation method in alkali media and were characterized by XRD, FTIR, TGA, VSM, TEM, and SEM. TGA and FTIR results confirmed the binding of thiodiglycol onto the surface of Fe3O4 nanoparticles. XRD pattern showed the presence of peaks corresponding to the inverse spinel structure of Fe3O4 nanoparticles. In addition, the magnetic properties of nanoparticles determined by VSM exhibited TDG-Fe 3O4 nanoparticles that have superparamagnetic property with high enough saturation magnetization of 44.55 emu/g. TEM and SEM results showed that TDG-Fe3O4 nanoparticles have good dispersion and are smaller and less agglomerated than pure Fe3O4 nanoparticles due to reduction in attractive forces between the nanoparticles by thiodiglycol. Additionally, the result of DTG analysis of TDG-Fe 3O4 nanoparticles suggested that thiodiglycol molecules were bonded to the surface of the Fe3O4 nanoparticles with different binding modes. © 2014 Elsevier Inc. Source

Mohammadi A.,University of Mazanadaran | Lakouraj M.M.,University of Mazanadaran | Barikani M.,Iran Polymer And Petrochemical Institute
Reactive and Functional Polymers

In this study, a new type of flexible polyurethane foam containing p-tert-butyl thiacalix[4]arene (TC4A) macrocycle was synthesized. TC4A macrocycle was incorporated into polyurethane foam as a part of crosslinking agent as well as glycerol. Structural, morphological, thermal and mechanical properties of this prepared foam were studied and compared with a polyurethane foam based on only glycerol as crosslinking agent, by Fourier transform infrared (FTIR), Scanning electron microscopy (SEM), Thermal gravimetric analysis (TGA), and dynamic mechanical thermal analysis (DMTA). The effect of introduction of TC4A crosslinker on cream time, rise time, apparent density, and water absorbency of the PU foams was evaluated. Moreover, it was shown that new TC4A-based polyurethane foam (TC-PUF) can be a high performance adsorbent for removal of malachite green from aqueous media using batch adsorption technique. The adsorption results indicated that TC-PUF has a high adsorption capacity of 58.82 mg/g for malachite green due to the presence of TC4A macrocycles in the structure of polyurethane foam. The kinetics of adsorption of malachite green was also investigated using the pseudo-first-order and pseudo-second-order kinetic models. The results of kinetic studies showed that the adsorption of malachite green onto TC-PUF followed pseudo-second-order kinetic model. © 2014 Elsevier Ltd. All rights reserved. Source

Mohammadi A.,University of Mazanadaran | Barikani M.,Iran Polymer And Petrochemical Institute | Lakouraj M.M.,University of Mazanadaran
Materials Science and Engineering C

In this study, a series of magnetic polyurethane/Fe3O4 elastomer nanocomposites were prepared by covalently embedding novel thiacalix[4]arenes (TC4As) functionalized Fe3O4 nanoparticles (TC4As-Fe3O4) which contain macrocycles with reactive hydroxyl groups. Surface functionalization of Fe3O4 nanoparticles with TC4As macrocycles as unique reactive surface modifier not only gives specific characteristics to Fe3O4 nanoparticles but also improves the interphase interaction between nanoparticles and the polyurethane matrices through covalent attachment of polymer chains to nanoparticle surfaces. The novel synthesized TC4As-Fe3O4 nanoparticles were characterized by FTIR, XRD, TGA, VSM and SEM analysis. Furthermore, the effect of functionalization of Fe3O4 nanoparticles on the various properties of resulting nanocomposites was studied by XRD, TGA, DMTA, SEM, and a universal tensile tester. It was found that the functionalization of nanoparticles with TC4As affords better mechanical and thermal properties to polyurethane nanocomposites in comparison with unmodified nanoparticles. The SEM analysis showed finer dispersion of TC4As-Fe3O4 nanoparticles than unmodified Fe3O4 nanoparticles within the polyurethane matrices, which arising from formation of covalent bonding between TC4As functionalized Fe3O4 nanoparticles and polyurethane matrices. Moreover, the investigation of in vitro biocompatibility of novel nanocomposites showed that these samples are excellent candidate for biomedical use. © 2016 Elsevier B.V. All rights reserved. Source

Mohammadi A.,University of Mazanadaran | Lakouraj M.M.,University of Mazanadaran | Barikani M.,Iran Polymer And Petrochemical Institute
Polymer International

A series of polyurethane elastomers containing various thiacalix[4]arene derivatives in a mixture with glycerol as chain extenders were synthesized. A series of polyurethane elastomers (PUEs) derived from three thiacalix[4]arene derivatives (TC4As), namely p-tert-butylthiacalix[4]arene, tetrasodium thiacalix[4]arenetetrasulfonate and thiacalix[4]arenetetrasulfonic acid, as a portion of chain extender in a mixture with glycerol were synthesized. The effects of the chemical structure of TC4As used as chain extenders on the various properties of the prepared PUEs were investigated and compared with PUE extended with only glycerol as chain extender using Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy and a universal tensile tester. Moreover, the effect of the introduction of TC4As as a portion of chain extender on the hydrophobicity of the PUEs was also evaluated. DSC, FTIR spectroscopy and XRD revealed that the degree of phase separation and crystallinity in TC4A-based PUEs was much higher than that of the glycerol-based ones. Thus, it was concluded that the presence of TC4As in TC4A-based PUEs seems to favour the formation of a more ordered structure due to an increase in the degree of phase separation. The TGA results also showed that, with incorporation of TC4As into the polyurethane backbone, the thermal stability of PUEs was improved. © 2014 Society of Chemical Industry. Source

Hamidinezhad H.,University of Mazandaran | Akbar Ashkarran A.,University of Mazanadaran | Abdul-Malek Z.,University of Technology Malaysia
Materials Science in Semiconductor Processing

Vertically aligned silicon nanowires (SiNWs) have been successfully synthesized using pure silane gas as a precursor by very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) method. The effect of the growth temperature on the morphology, structure and photoluminescence properties of SiNWs has been studied. The SiNWs were needle-liked materials with the length of a few microns having the diameters of tens of nanometers near the bottom and a few nanometers at the top. Thinner nanowires have been obtained at the higher growth temperature process. High resolution transmission electron microscopy confirms that the nanowires are composed of a crystalline silicon core with an oxide shell. The PL spectrum of the Si nanoneedles have shown two emission bands around 450 nm and ∼750, which originate from the defects related to oxygen fault in the oxide shell and interfaces between the crystalline Si core and the oxide shell, respectively. © 2014 Elsevier Ltd. Source

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