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    Electron beam induced crosslinking of nylon 6 with and without the presence of TAC

    , Article Polymer Degradation and Stability ; Volume 89, Issue 3 , 2005 , Pages 436-441 ; 01413910 (ISSN) Dadbin, S ; Frounchi, M ; Goudarzi, D ; Sharif University of Technology
    The influence of electron beam irradiation on neat nylon 6 was manifested by formation of molecular branches deduced from increase in melt flow index and intrinsic viscosity. Crosslinking of nylon 6 was carried out using electron beam irradiation in presence of triallyl cyanurate (TAC). The crosslinked samples showed a high level of gel content. At a given dose, increasing the TAC level from 1% to 3% increased the gel content of the samples slightly and correspondingly decreased the percent of water absorption. The melting temperature decreased with increasing the dose and the TAC level. All samples containing TAC showed some decrease in crystallinity under exposure to electron beam. The... 

    Preparation of highly rubber-toughened nylons

    , Article Iranian Polymer Journal (English Edition) ; Volume 16, Issue 7 , 2007 , Pages 459-468 ; 10261265 (ISSN) Bordbar, H ; Yousefi, A. A ; Ramezani saadatabadi, A ; Sharif University of Technology
    Nylon 6 and 66 were toughened with EPDM-g-MA and SEBS-g-MA and steadystate rheological behaviour of rubbers, nylons and their blends and mechanical properties of nylons and their rubber-toughened blends were investigated. The EPDM maleic grafting preparation was performed In the framework of this study where SEBS-g-MA was obtained from a commercial source. The results showed the ultratoughened SEBS-g-MA blends, whereas EPDM blends under the same blending conditions did not show a significant improvement in toughness. In case of EPDM toughened blends an average of some micrometers was observed for the dispersed EPDM particles. Impact and tensile properties of the toughened blend with 20% of... 

    Investigation of vacuum annealing effects on physical-mechanical properties of thermoplastic parts

    , Article Materials and Design ; Volume 26, Issue 1 , 2005 , Pages 89-93 ; 02613069 (ISSN) Ramazani, A ; Mousavi, S ; Sharif University of Technology
    Elsevier Ltd  2005
    Impact and tensile strength of polystyrene and nylon 6 samples, which have been produced by injection molding before and after annealing in different conditions are obtained. Polystyrene samples that are heated on vacuum conditions can deform highly even in temperatures much less than polystyrene glass temperature. This phenomenon is reduced significantly by heating samples to annealing temperature in atmospheric pressure and then removing air from sample environment in constant temperature. Deformation problems for nylon were not so important but due to high temperature implied for annealing of nylon parts, some color change due to oxidative degradation are observed. So for nylon parts a... 

    Polypyrrole/polyamide electrospun-based sorbent for microextraction in packed syringe of organophosphorous pesticides from aquatic samples

    , Article Journal of Separation Science ; Volume 35, Issue 1 , December , 2012 , Pages 114-120 ; 16159306 (ISSN) Bagheri, H ; Ayazi, Z ; Aghakhani, A ; Alipour, N ; Sharif University of Technology
    A novel method based on microextraction in packed syringe (MEPS) as sample preparation technique coupled off-line with gas chromatography-mass spectrometry was developed using electrospun nanofibers as sorbent. For electrospinning of polypyrrole/polyamide-based nanofiber, a homogeneous solution containing nylon 6, ferric chloride and pyrrole monomer was prepared and then was drawn into a 2.5-mL syringe. By applying a voltage of 13akV between the needle of the syringe and an aluminum-foil collector, the nanofibers could be formed on the surface of the collector. The prepared sheet was used as the sorbent for MEPS to analyze some selected organophosphorous pesticides. Important parameters... 

    Natural compounds for skin tissue engineering by electrospinning of nylon-Beta vulgaris

    , Article ASAIO Journal ; Volume 64, Issue 2 , 2018 , Pages 261-269 ; 10582916 (ISSN) Ranjbarvan, P ; Mahmoudifard, M ; Kehtari, M ; Babaie, A ; Hamedi, S ; Mirzaei, S ; Soleimani, M ; Hosseinzadeh, S ; Sharif University of Technology
    Lippincott Williams and Wilkins  2018
    Natural compounds containing polysaccharide ingredients have been employed as candidates for treatment of skin tissue. Herein, for the first time, electrospinning setup was proposed to fabricate an efficient composite nanofibrous structure of Beta vulgaris (obtained from Beet [Chenopodiaceae or Amaranthaceae]) belonged to polysaccharides and an elastic polymer named nylon 66 for skin tissue engineering. Both prepared scaffolds including noncomposite and composite types were studied by Scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy, mechanical assay, and contact angle. Scanning electron microscope examinations have approved the uniform and homogeneous... 

    Investigation the Effect of Conductive Scaffolds on Regeneration of the Heart Tissue

    , M.Sc. Thesis Sharif University of Technology Moradpour, Kayvan (Author) ; Vossoughi, Manoochehr (Supervisor) ; Ahmadi Tafti, Hossein (Supervisor)
    Cardiovascular diseases, especially coronary artery disease and coronary heart disease, are the leading cause of death in human communities. After myocardial infarction, known as heart attack, the flow of oxygen to the heart muscle cells is disrupted. It causes the death of cells that leads to structural and functional changes in the heart muscle. Therefore, specialists try to find a way to repair and regenerate the heart muscle after myocardial infarction. Tissue engineering is used to develop substantial alternatives to assist clinical therapies. Recent studies have focused on the construction of scaffolds with various advanced techniques to create guiding channels that mimic the natural... 

    Electrospun decyl-3-methylimidazolium mono bromate/polyamide nanofibers as solid-phase microextraction coating

    , Article Journal of Chromatography A ; Volume 1516 , 2017 , Pages 35-41 ; 00219673 (ISSN) Roostaie, A ; Rastegar, S ; Najarzadegan, H ; Ehteshami, S ; Sharif University of Technology
    In the current study, electrospun-based ionic liquid (IL) doped polyamide (PA) nanofibers were prepared and used as the coating material of solid phase microextration device in the fiber geometry. Addition of IL, decyl-3-methylimidazolium mono bromate, increased the conductivity of the PA solution facilitating the electrospining process. The scanning electron microscopy images of decyl-3-methylimidazolium mono bromated/polyamide nanofibers showed the decreased diameter of the nanofibers in the range of 35–160 nm compared to the PA nanofiber. The factors affecting the structure of nanofibers (e.g. ratio of decyl-3-methylimidazolium mono bromate to PA, coating time and applied voltage) were... 

    Novel polyamide-based nanofibers prepared by electrospinning technique for headspace solid-phase microextraction of phenol and chlorophenols from environmental samples

    , Article Analytica Chimica Acta ; Volume 716 , 2012 , Pages 34-39 ; 00032670 (ISSN) Bagheri, H ; Aghakhani, A ; Baghernejad, M ; Akbarinejad, A ; Sharif University of Technology
    A novel solid phase microextraction (SPME) fiber was fabricated by electrospinning method in which a polymeric solution was converted to nanofibers using high voltages. A thin stainless steel wire was coated by the network of polymeric nanofibers. The polymeric nanofiber coating on the wire was mechanically stable due to the fine and continuous nanofibers formation around the wire with a three dimensional structure. Polyamide (nylon 6), due to its suitable characteristics was used to prepare the unbreakable SPME nanofiber. The scanning electron microscopy (SEM) images of this new coating showed a diameter range of 100-200nm for polyamide nanofibers with a homogeneous and porous surface... 

    Polyaniline-nylon-6 electrospun nanofibers for headspace adsorptive microextraction

    , Article Analytica Chimica Acta ; Volume 713 , 2012 , Pages 63-69 ; 00032670 (ISSN) Bagheri, H ; Aghakhani, A ; Sharif University of Technology
    A headspace adsorptive microextraction technique was developed using a novel polyaniline-nylon-6 (PANI-N6) nanofiber sheet, fabricated by electrospinning. The homogeneity and the porosity of the prepared PANI-N6 sheet were studied using the scanning electron microscopy (SEM) and nanofibers diameters were found to be around 200nm. The novel nanofiber sheet was examined as an extracting medium to isolate some selected chlorobenzenes (CBs), as model compounds, from aquatic media. The extracted analytes were desorbed using μL-amounts of solvent and eventually an aliquot of extractant was injected into gas chromatography-mass spectrometry (GC-MS). Various parameters affecting the extraction and... 

    Polyamide/titania hollow nanofibers prepared by core–shell electrospinning as a microextractive phase in a fabricated sandwiched format microfluidic device

    , Article Journal of Chromatography A ; Volume 1528 , 2017 , Pages 1-9 ; 00219673 (ISSN) Rezvani, O ; Hashemi Hedeshi, M ; Bagheri, H ; Sharif University of Technology
    In this study, a low–cost microfluidic device from polymethyl methacrylate was fabricated by laser engraving technique. The device is consisted of a central chip unit with an aligned microchannel. Both sides of the engraved microchannel were sandwiched by two synthesized sheets from polyamide/titania (PA/TiO2) hollow nanofibers as extractive phases. The inlet and outlet of the device were connected to the polyether ether ketone tubes, while a peristaltic pump was used to deliver both sample and desorbing solvent through the microchannel. The recorded scanning electron microscopy images from the surface of the synthesized PA/TiO2 nanofibers, exhibit a good degree of homogeneity and porosity... 

    Study of epithelial differentiation and protein expression of keratinocyte-mesenchyme stem cell co-cultivation on electrospun nylon/B. vulgaris extract composite scaffold

    , Article Materials Science and Engineering C ; Volume 75 , 2017 , Pages 653-662 ; 09284931 (ISSN) Hosseinzadeh, S ; Soleimani, M ; Vossoughi, M ; Ranjbarvan, P ; Hamedi, S ; Zamanlui, S ; Mahmoudifard, M ; Sharif University of Technology
    Employing of the composite electrospun scaffold containing herbal extract in conjugation with co-culturing of cells can open up new window to the design of efficient biomaterials for skin tissue regeneration. Here, we introduce the synergistic effect of composite electrospun nanofibrous scaffold of nylon66 loaded with Beta vulgaris (B. vulgaris) (extract of beet roots, a plants whose widely used in Iranian folk medicine as wound healing medicine) and co-culture of mesenchymal stem-cells (MSCs)-human keratinocyte (H-keratino) differentiation towards epithelial lineage. In vitro biocompatibility was examined through MTT assay and epithelial differentiation checked by real-time PCR and... 

    Synthesis and properties of novel fluorinated polyamides based on noncoplanar sulfoxide containing aromatic bis(ether amine)

    , Article Polymer Journal ; Volume 41, Issue 3 , 2009 , Pages 174-180 ; 00323896 (ISSN) Shockravi, A ; Abouzari Lotf, E ; Javadi, A ; Taheri, S ; Sharif University of Technology
    A novel sulfoxide containing bis(ether amine) monomer, 2,2'-sulfoxide- bis[4-methyl(2-trifluoromethyl)4-aminophenoxy) phenyl ether] (M2), was synthesized from the halogen displacement of 2-chloro-5-nitrobenzotrifluoride with dibenzosulfoxide (DH) in the presence of potassium carbonate, followed by catalytic reduction of bis(ether nitro) intermediate with Zinc/Ammonium chloride. A series of organic-soluble poly(ether amide)s (PA1-7) bearing sulfoxide and electronwithdrawing trifiuoromethyl group were synthesized from bis(ether amine) with various aromatic diacids (1-7) via a direct polycondensation with triphenyl phosphite and pyridine. The resulting polymers had inherent viscosities ranging...