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    Efficient inductively heated shape memory polyurethane acrylate network with silane modified nanodiamond@Fe3O4 superparamagnetic nanohybrid

    , Article European Polymer Journal ; Volume 159 , 2021 ; 00143057 (ISSN) Salkhi Khasraghi, S ; Shojaei, A ; Janmaleki, M ; Sundararaj, U ; Sharif University of Technology
    Elsevier Ltd  2021
    Multifunctional magnetic shape memory polymer (SMP) nanocomposites with high sensitivity was synthesized through inclusion of silane functionalized nanodiamond@Fe3O4 (S-NDF) hybrid nanoparticle into polycaprolactone (PCL) based polyurethane acrylate (PUA) matrix followed by in situ crosslinking of the matrix. Highly biocompatible and superparamagnetic nanodiamond(ND)@Fe3O4 nanohybrids were synthesized through in situ co-precipitation method. The morphological analysis suggested that S-NDFs filled PUAs (2 to 9 wt% loadings) well interacted with both soft and hard domains of the matrix. The base polymer and the nanocomposites presented excellent shape fixity ratio (above 97%) and shape... 

    Multiscale modeling of the effect of carbon nanotube orientation on the shear deformation properties of reinforced polymer-based composites

    , Article Physics Letters, Section A: General, Atomic and Solid State Physics ; Volume 375, Issue 14 , 2011 , Pages 1588-1597 ; 03759601 (ISSN) Montazeri, A ; Sadeghi, M ; Naghdabadi, R ; Rafii Tabar, H ; Sharif University of Technology
    A combination of molecular dynamics (MD), continuum elasticity and FEM is used to predict the effect of CNT orientation on the shear modulus of SWCNT-polymer nanocomposites. We first develop a transverse-isotropic elastic model of SWCNTs based on the continuum elasticity and MD to compute the transverse-isotropic elastic constants of SWCNTs. These constants are then used in an FEM-based simulation to investigate the effect of SWCNT alignment on the shear modulus of nanocomposites. Furthermore, shear stress distributions along the nanotube axis and over its cross-sectional area are investigated to study the effect of CNT orientation on the shear load transfer  

    Polymer matrix nanocomposites for heavy metal adsorption: a review

    , Article Journal of the Iranian Chemical Society ; Volume 17, Issue 6 , 31 January , 2020 , Pages 1259-1281 Mohammadnezhad, G ; Keikavousi Behbahan, A ; Sharif University of Technology
    Springer  2020
    Heavy metals belong to a group of lethal environmental pollutants. Ongoing efforts targeted at safeguarding public health have led to considerable attention being focused on methods that allow efficient extraction of these toxic substances. Polymer nanocomposites (PNCs) with their special characteristics are a class of adsorbents that demonstrate high potential for use in heavy metal extraction. As this process of removal is predominantly governed by adsorption, various parameters in PNCs’ chemical structure, as well as the metal solutions, can have a significant effect on the adsorption process. Herein, this review undertakes a survey of recently developed PNCs and their metal adsorption... 

    Contribution of ordered-inordered phenomenon within the interphase region toward increasing elastic modulus in CNT/polymer nanocomposites

    , Article Materials Science and Technology Conference and Exhibition 2015, MS and T 2015, 4 October 2015 through 8 October 2015 ; Volume 1 , October , 2015 , Pages 595-602 ; 9781510813939 (ISBN) Shayesteh Zeraati, A ; Goodarzi Hosseinabadi, H ; NACE International ; Sharif University of Technology
    Association for Iron and Steel Technology, AISTECH  2015
    Exceptional mechanical properties of carbon nanotubes (CNTs) such as high elastic modulus, stiffness and tensile strength have made them as promising reinforcement in polymer nanocomposite systems. The characteristics of CNTs/polymer interphase region directly affect the efficiency of nanotubes for improving the nanocomposite mechanical properties. In this work, the influence of chains alignment within the interphase region on elastic response of the nanocomposite is assessed using a novel ordered-inordered approach. The applicability of the presented approach is examined by implementing the approach on a series of reported data available in the literature. The effects of CNT content,... 

    Heterogeneities in polymer structural and dynamic properties in graphene and graphene oxide nanocomposites: molecular dynamics simulations

    , Article Macromolecular Theory and Simulations ; Volume 26, Issue 2 , 2017 ; 10221344 (ISSN) Azimi, M ; Mirjavadi, S. S ; Salem Hamouda, A. M ; Makki, H ; Sharif University of Technology
    Wiley-VCH Verlag  2017
    The effect of graphene (G) and graphene oxide (GO), used as the nanofiller in polymer nanocomposites (NC), on the structural and dynamic properties of polymer chains, has been studied by means of molecular dynamics (MD) simulations. Two polymers, i.e., poly(propylene) and poly(vinyl alcohol), are employed as matrices to cover a wider range of polymer–filler interactions. The local structural properties, e.g., density profile, average Rg, and end-to-end distance as well as dynamic properties, e.g., estimated translational and orientational relaxation times, of polymer chains are studied. In addition, the interaction energies are estimated between polymers and nanofillers for different hybrid... 

    Synthesis of Graphene Oxide-based Polymer Nanocomposites and Investigation of Their Ability in Dye Adsorption

    , Ph.D. Dissertation Sharif University of Technology Nazari, Mojtaba (Author) ; Pourjavadi, Ali (Supervisor)
    In this project, polymer nanocomposites containing graphene oxide were prepared and used for adsorption of several cationic and anionic dyes. In most cases, these nanocomposites were prepared as three-dimentional polymer networks which contain graphene oxide. Nanocomposites with direct grafting of polymer chains onto the surface of graphene oxide were also prepared. Graphene oxide is an oxidized carbonaceous material with unique properties. This material has high surface area, good mechanical strength and various functional groups. Polymeric compounds with different functional groups, structures and properties can be prepared and used. By preparing composites of graphene oxide and polymers,... 

    Mechanical & Microstructural Evaluations of (High MFI PP/Low MFI PP)/Organoclay Nanocomposites Influence of Clay Loading, Compatibilizer Loading and Processing Sequence

    , M.Sc. Thesis Sharif University of Technology Darestani Farahani, Amir (Author) ; Bagheri, Reza (Supervisor)
    Polymer/layered silicate nanocomposites are good candidates to improve polymer matrices due to enhanced interfaces between nanoclay reinforcement and matrix. So many attempts has been done to improve fabrication methods of these nanocomposites. Polypropylene is a common used engineering material in many industrial applications (general and special). So there is many researches focused on PP/Clay nanocomposites. In this research we tried to investigate the role of clay loading, compatibilizer loading and processing sequence on clay delamination and layer dispersion. We used a blend of two different PPs with different MFI values as matrice. It seems that the blend achieves acceptable... 

    Preparation and Characterization of Metal-Organic Framework/Chitosan Nanocomposites to Dye Removal from Aqueous Media

    , M.Sc. Thesis Sharif University of Technology Noori, Farnaz (Author) ; Shojaei Segherloo, Akbar (Supervisor) ; Molavi, Hossein (Co-Supervisor)
    The amino groups present in the chemical structure of chitosan have made this material a prominent dye absorbents. But researchers have always taken steps to improve conditions and increase absorption. One of the materials that has attracted most researchers today is metal-organic frameworks. These porous materials with high surface area, optimum thermal resistance and adsorbent dye functional groups have been used as the reinfocing in the chitosan polymer field to adsorb anionic dye (methyl orange) from the aqueous media. One of metal-organic frameworks is UiO-66, which was selected as a reinforcing phase in the polymer field, due to its good stability in aqueous solutions, good thermal... 

    Property Investigation of Poly (Ethylene Co-vinyl Acetate)/Poly (l-Lactic Acid)/Organo Clay Nanocomposites

    , Article Journal of Polymers and the Environment ; Volume 27, Issue 12 , 2019 , Pages 2886-2894 ; 15662543 (ISSN) Torabi, H ; Ramazani SaadatAbadi, A ; Sharif University of Technology
    Springer New York LLC  2019
    In this study, EVAc/PLA/organo clay nanocomposites were prepared via solution mixing method. The SEM images were used to investigate the morphology of nanocomposites revealing no phase separation or agglomeration of disperse phase in EVAc/PLA blends and nanocomposites. SAXS spectra confirmed the intercalated morphology of nanocomposites. Soil burial test were carried out and the rate of degradation of the samples were measured indirectly. Oxygen gas permeability of EVAc was slightly decreased by adding PLA to the matrix, when small loads of clay caused dramatic improvement in barrier properties. Melt rheological frequency sweep test illustrated the compatibility of EVAc with low contents of... 

    Effect of interphase zone on the overall elastic properties of nanoparticle-reinforced polymer nanocomposites

    , Article Journal of Composite Materials ; Volume 53, Issue 9 , 2019 , Pages 1261-1274 ; 00219983 (ISSN) Amraei, J ; Jam, J. E ; Arab, B ; Firouz Abadi, R. D ; Sharif University of Technology
    SAGE Publications Ltd  2019
    In the current work, the effect of interphase region on the mechanical properties of polymer nanocomposites reinforced with nanoparticles is studied. For this purpose, a closed-form interphase model as a function of radial distance based on finite-size representative volume element is suggested to estimate the mechanical properties of particle-reinforced nanocomposites. The effective Young’s and shear moduli of thermoplastic polycarbonate-based nanocomposites for a wide range of sizes and volume fractions of silicon carbide nanoparticles are investigated using the proposed interphase model and molecular dynamics simulations. In order to investigate the effect of particle size, several unit... 

    Experimental Studies and Finite Element Analysis of Polymer Nanocomposites Reinforced with Graphene Sheets under Impact Loading

    , M.Sc. Thesis Sharif University of Technology Zarei Darani , Sajad (Author) ; Naghdabadi, Reza (Supervisor) ; Sohrabpour, Saeed (Supervisor)
    In the experimental approach, graphene and Graphene Oxide (GO) were synthesized through a chemical method. In order to study the quality of GO, characterization tests were performed. Then, reinforced polymer with GO and graphene was made. Moreover, tension, compression and Split- Hopkinson pressure bar tests were performed on standard samples of reinforced polymer nanocomposite. The experimental data show that nanoparticles have a destructive effect in very low and high percentages for extension test as well as in high percentages for compression test. On the other hand, graphene is more effective than GO on improving material properties. Furthermore, comparison of compression results in... 

    Investigation of Carbon Nanotube-Polymer Composites Thermal Conductivity Using Molecular Dynamics Simulations

    , Ph.D. Dissertation Sharif University of Technology Gharib-Zahedi, Mohammad Reza (Author) ; Tafazzoli, Mohsen (Supervisor) ; Alaghemandi, Mohammad (Co-Advisor)
    In the present research, we have applied reverse non-equilibrium molecular dynamics (RNEMD) to investigate the thermal conductivity (λ) of carbon nanotube (CNT) bundles, CNT-polyamide (PA) nanocomposites, and nanoconfined PA in the vicinity of graphene layers. First, transversal heat transport in CNT bundles with and without intertube chemical bonds are examined. It is found that the transversal λ of samples with cross linkers can surprisingly increase ~9 times than that of neat CNT bundles (0.26 W m-1K-1). According to the simulation results, key parameters are overlapping vibrational density of state (DOS) profiles between the atoms forming the bridging units, cross linker in the direction... 

    A Multi-scale Solution for Prediction of Mechanical Properties of Polymeric Nano Carbon Nanocomposites with Using Stochastic Approach

    , M.Sc. Thesis Sharif University of Technology Jazzab, Mohammad Javad (Author) ; Hosseini Kordkheili, Ali (Supervisor)
    The use of nanocomposite materials in various industries such as aerospace, oil and gas, automotive, etc. has become increasingly widespread due to its unique thermal and mechanical properties. Due to the problems and costs of the production process and experimental testing for optimal construction, it is necessary to propose a low-cost method for estimating the mechanichal properties of these materials. In this research, the mechanical properties of polymetric nano carbon nanocomposites have been estimated by multi-scale method with using finite element analysis by Abaqus software. the mechanical properties of nanocarbon composites have been extracted by using the multi-scale method that... 

    Preparation of Electro Conductive-piezoelectric Nanocomposite for Cartilage Tissue Engineering

    , M.Sc. Thesis Sharif University of Technology Bagheri, Lida (Author) ; Ramazani, Ahmad (Supervisor) ; Nasrollahzadeh, Naser (Co-Supervisor)
    Articular cartilage resides in a complex and dynamic mechanical and biophysical environment in vivo. Chondrocyte physiology and biosynthetic activity is influenced by these signals, allowing them to modulate the structural organization and function of tissue at all stages, including development, growth and repair. . In articular cartilage, during physical activity and mechanical loading, electric signal have been observed in form of stress-generated electric potential following the movement of the positive mobile ions (in interstitial fluid) away from the fixed negative charges.Despite increasing evidence that mechanical and electrical stimuli have positive effects on chondrogenesis, to... 

    Development of Modified Nanostructures for Fabrication of Polymer Nanocomposite Films for Controlled Atmosphere Food Packaging

    , Ph.D. Dissertation Sharif University of Technology Riahi, Zohreh (Author) ; Bagheri, Reza (Supervisor) ; Pircherghi, Gholamreza (Supervisor) ; Mohammadpour, Raheleh (Co-Supervisor)
    Active packaging is a novel approach that can ensure food safety by removing undesirable compounds such as Oxygen, ethylene, moisture, and microbial contamination from fresh produce's environment and reducing product loss by extending shelf life. Current research on active food packaging materials focuses on using biopolymers such as carbohydrates, proteins, and lipids as alternatives to non-degradable petroleum-based packaging materials. Active nanomaterials are commonly used to impart functionality to packaging materials. However, the lack of functionality limits their industrial application.Therefore, the main objective of this work was to fabricate bioactive nanocomposite films by... 

    Investigation of Nanocellulose Performance on the Corrosion Control in Polymeric Coating

    , M.Sc. Thesis Sharif University of Technology Shahnavaz, Alireza (Author) ; Shojaei, Akbar (Supervisor)
    Cellulose nanocrystals as a reinforcement in polymer nanocomposites are part of current research for reasons such as source renewable, biocompatibility, nanoscale dimensions, high specific surface area, and surface chemistry. This research used cellulose nanocrystals as a corrosion inhibitor carrier in epoxy-based composite with 1% by weight. In order to load the corrosion inhibitor, firstly, cellulose nanocrystals were surface modified by aniline so that they can spread well in the hydrophobic epoxy matrix. Different corrosion inhibitors were tested for adsorption on the surface of cellulose nanocrystals modified with polyaniline, but finally the acidic agent of phosphoric acid showed... 

    Improvement in mechanical performance of anionic hydrogels using full-interpenetrating polymer network reinforced with graphene oxide nanosheets

    , Article Advances in Polymer Technology ; Volume 35, Issue 4 , 2016 , Pages 386-395 ; 07306679 (ISSN) Kheirabadi, M ; Bagheri, R ; Kabiri, K ; Ossipov, D. A ; Jokar, E ; Asadian, E ; Sharif University of Technology
    John Wiley and Sons Inc 
    Weak mechanical possession is one of the limiting factors in application of hydrogels. To modify this inherent disadvantage, different approaches have been studied including synthesizing interpenetrating polymer network (IPN) and nanocomposite hydrogels. So, this study has focused on preparation of a novel full-IPN structure based on anionic monomers of 2-acrylamido-2-methylpropane sulfonic acid/acrylic acid–sodium acrylate via facile solution polymerization technique in an aqueous media with incorporation of graphene oxide (GO) nanosheets. Mechanical performance of materials in the “as-prepared condition” and “swollen state” was characterized via tensile, compression, and rheology tests,... 

    Investigation the stability of SWCNT-polymer composites in the presence of CNT geometrical defects using multiscale modeling

    , Article 4th International Conference on Multiscale Materials Modeling, MMM 2008, 27 October 2008 through 31 October 2008 ; 2008 , Pages 163-166 ; 9780615247816 (ISBN) Montazeri, A ; Naghdabadi, R ; Sharif University of Technology
    Department of Scientific Computing, Florida State University  2008
    CNT-reinforced polymer composites have attracted attention due to their exceptional high strength. The high strength can be affected by the presence of defects in the nanotubes used as reinforcements in the practical nanocomposites. In this paper, a Molecular Structural Mechanics / Finite Element (MSM/FE) multiscale modeling is used to study the effect of carbon nanotube geometrical defects on the stability of SWCNT-polymer composites. Here, two types of representative volume elements (RVEs) for these nanocomposites are considered with perfect and defected CNT. These RVEs have the same dimensions. The nanotube is modeled at the atomistic scale using molecular structural mechanics whereas the... 

    hysical and Chemical Surface Modification of Titanium by Nanostructured Materials, and Biological Characterization for Use in Bone Tissue Implants

    , Ph.D. Dissertation Sharif University of Technology Rahnamaee, Yahya (Author) ; Bagheri, Reza (Supervisor) ; Vossoughi, Manochehr (Supervisor) ; Samadi Kuchaksaraei, Ali (Supervisor)
    According to human needs and in line with the development of advanced technologies, different biomedical Engineering fields like hard tissue implants are growing rapidly. Despite significant biotechnology Developments in recent years, some problems to the recognition of implants related osseointegration phenomena persist. The deficient osseointegration and implant-associated infections are key issues for the long-term clinical success of titanium and titanium alloy implants, while development of multifunctional surfaces that can simultaneously overcome these problems remains highly challenging. Therefore, the ultimate goal of this paper was to improve bone cell attachment and simultaneously... 

    Evaluation of interfacial layer properties in the polystyrene/silica nanocomposite

    , Article Journal of Applied Polymer Science ; Volume 119, Issue 4 , August , 2011 , Pages 2039-2047 ; 00218995 (ISSN) Mortezaei, M ; Farzi, G ; Kalaee, M. R ; Zabihpoor, M ; Sharif University of Technology
    Processing conditions and final mechanical properties of polymer nanocomposites are affected by their interfacial layers behavior. However, it is impossible to determine directly the properties of these layers by dynamic rheometry tests. In this work, the interfacial layers properties are evaluated for polystyrene containing silica nanoparticles by the concept of glass-transition temperature shift. The samples were prepared via solution-mixing method and dynamic rheometry was used to determine the viscoelastic behavior of filled polymers in the melt state. This initial step showed that addition of silica particles increased the glass-transition temperature. By preference, decrease in the...