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polymer-composite
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Polymer/nanodiamond composites - a comprehensive review from synthesis and fabrication to properties and applications
, Article Advances in Colloid and Interface Science ; Volume 269 , 2019 , Pages 122-151 ; 00018686 (ISSN) ; Salkhi Khasraghi, S ; Hashemi, M ; Rabiei, S ; Shojaei, A ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Nanodiamond (ND)is an allotrope of carbon nanomaterials which exhibits many outstanding physical, mechanical, thermal, optical and biocompatibility characteristics. Meanwhile, ND particles possess unique spherical shape containing diamond-like structure at the core with graphitic carbon outer shell which intuitively contains many oxygen-containing functional groups at the outer surface. Such superior properties and unique structural morphology of NDs are essentially attractive to develop polymer composites with multifunctional properties. However, despite a long history from the discovery of NDs, which is dated back to the1960s, this nanoparticle has been less explored in the field of...
Thermal synergistic effect in hybrid filler epoxy composites consisting of graphene nanoplatelets and SiC particles
, Article Thermal Science and Engineering Progress ; Volume 25 , 2021 ; 24519049 (ISSN) ; Kazemi Ranjbar, S ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
The use of hybrid filler is a promising strategy for development of thermally conductive polymer composites. This paper reported the measurement of thermal conductivity of the epoxy composite filled with a hybrid filler of graphene nanoplatelet (GNP) and silicon carbide (SiC) microparticles. For this hybrid filler, the effect of the average size of SiC on composite thermal conductivity was examined. The results showed that the thermal synergistic effect was highly affected by the average size of the SiC. By using a hybrid filler of 11% vol. GNP and 9% vol. 1 µm-size SiC micro-particles thermal conductivity has reached 3.44 W m−1 K−1. This value is 42% higher than the thermal conductivity of...
Optimization of Nanostructure, Mechanical Properties and Flammability of Polypropylene/Nanoclay/Flame Retardant Additive Ternary Compounds
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Reza (Supervisor)
Abstract
Today, in many industries polypropylene is used as a polyolefin with favorable properties such as chemical resistance, fatigue strength, electrical insulation, as well as good mechanical properties such as high Yang modulus, good toughness, and so on. On the other hand, polyolefins have poor thermal resistance and high flammability. Over the years, many researchers have been working to reduce their flammability through different methods and increase their thermal resistance. Among these methods, adding materials that delayed flammability or stoped it, can be noted. In the industry, these anti-flammable additives are called flame retardants. Flame retardant additives should be selected to...
Investigating the effect of carbon nanotube defects on the column and shell buckling of carbon nanotube-polymer composites using multiscale modeling
, Article International Journal for Multiscale Computational Engineering ; Volume 7, Issue 5 , 2009 , Pages 431-444 ; 15431649 (ISSN) ; Naghdabadi, R ; Sharif University of Technology
2009
Abstract
Carbon nanotube (CNT)-reinforced polymer composites have attracted great attention due to their exceptionally high strength. Their high strength can be affected by the presence of defects in the nanotubes used as reinforcements in practical nanocomposites. In this article, a new three-phase molecular structural mechanics/finite element (MSM/FE) multiscale model is used to study the effect of CNT vacancy defects on the stability of single-wall (SW) CNT-polymer composites. The nanotube is modeled at the atomistic scale using MSM, whereas the interphase layer and polymer matrix are analyzed by the FE method. The nanotube and polymer matrix are assumed to be bonded by van der Waals interactions...
Preparation and Characterization of Supercapacitor Nanocomposites Based on Polyaniline and Hybrid of Nano Metal/Metal Oxide Particles
, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar (Supervisor)
Abstract
Supercapacitors are one of the most important energy storage devices that have been researched with respect to the development of hybrid cars. Polymer composites have received much attention due to the electrochemical properties of conductive polymers and the synergistic effects of the composite components. In the present Thesis, in order to investigate the synergistic effect of gold nanoparticles with MnO2 nanorods as a metal oxide and polyaniline as a conductive polymer and graphene as a carbon material, two groups of composites were synthesized in the presence and absence of graphene. Characterization of the electrode material is carried out by XRD, FT-IR and FE-SEM tests. The...
Improvement of Polymer Composites Thermal Conductivity by Nanoparticles
, M.Sc. Thesis Sharif University of Technology ; Nouri Broujerdi, Ali (Supervisor)
Abstract
The new generation of electronic devices including 5G internet, wearable electronics, LED optoelectronics or cloud computing devices have higher power density as their computing power increases and their sizes reduce. The increase in power density leads to higher heat generation and consequently higher operating temperature which reduces their lifetime and reliability. In recent years development of novel solutions for electronic cooling has been persued. Thermal interface material that inserted between heat source and heat sink is the main component in electronic cooling. These materials consists of a polymeric base that filled with highly thermally conductive solid particles. By emergence...
Parametric study of strain rate effects on nanoparticle-reinforced polymer composites
, Article Journal of Nanomaterials ; Volume 2016 , 2016 ; 16874110 (ISSN) ; Haji Gholami, I ; Masajedian, S ; Mertiny, P ; Sameoto, D ; Taheri, F ; Sharif University of Technology
Hindawi Publishing Corporation
2016
Abstract
Crashworthiness, energy absorption capacity, and safety are important factors in the design of lightweight vehicles made of fiber-reinforced polymer composite (FRP) components. The relatively recent emergence of the nanotechnology industry has presented a novel means to augment the mechanical properties of various materials. As a result, recent attempts have contemplated the use of nanoparticles to further improve the resiliency of resins, especially when resins are used for mating FRP components. Therefore, a comprehensive understanding of the response of nanoreinforced polymer composites, subjected to various rates of loading, is of paramount importance for developing reliable structures....
Mechanical strength of CFRP and GFRP composites filled with APP fire retardant powder exposed to elevated temperature
, Article Fire Safety Journal ; Volume 115 , 2020 ; Majdabadi Farahani, E ; Yekrangnia, M ; Ozbakkaloglu, T ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Ammonium polyphosphate (APP) is one of the most widely used halogen-free flame retardant, added in various resins to improve the fire properties, such as flame and smoke spread ratings and LOI, of fiber-reinforced polymer (FRP) composites. This paper experimentally investigates the effects of using APP, as a fire-retardant filler, on mechanical properties (i.e. ultimate tensile, flexural, and bond strength) of glass fiber-reinforced polymer (GFRP) and carbon fiber-reinforced polymer (CFRP) composites. Based on two fiber types (i.e. carbon and glass) and three different APP mass fractions in resin (i.e. 0, 20, and 40% of total weight of matrix), six sets of specimens were prepared for each...
The Evaluation of Different Parameters on Fatigue Life of Carbon / Epoxy and Carbon / Phenolic Polymer Composite Rods under Tensile-pressure Loads
, M.Sc. Thesis Sharif University of Technology ; Hosseini Kordkheili, Ali (Supervisor)
Abstract
The aim of this dissertation is to analyze the tensile-stress fatigue of composite rods made of a combination of carbon-epoxy resin as well as carbon chopped-phenolic resin and to investigate the effect of different parameters on their fatigue life. The curing process is completely different in carbon / epoxy and carbon / phenolic composites, Carbon / Epoxy is a thermo-plastic composite, but carbon / phenolic is a thermo- set composite. Therefore, differences in the curing process, raw materials, changes in the volume percentage of resin and fibers, the effects of different loading during the production and curing process of the composite, cooling and heating rates during production can...
Studying and Reviewing the Modification, Completion or Change of the Classical Theories Used in the Simulation of Resin Injection Network for Manufacturing of a Large Composite Structure by Means of Vacuum Infusion Process
, M.Sc. Thesis Sharif University of Technology ; Abedian, Ali (Supervisor)
Abstract
In recent years, liquid resin injection processes for aviation applications have been considered an alternative to conventional autoclave-based processes. At present, these processes have challenges that have been denied industry trust due to their inability to be objectively reproducible. In the last decade, some software has been developed to simulate the vacuum injection process, but this software does not have enough capability to predict the injection network, and an operator with sufficient empirical knowledge must use this software. In recent years, researchers have used this softwares to simulate the process, but so far no software has been developed that can offer injection...
Steady-state creep analysis of polymer matrix composites using complex variable method
, Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 227, Issue 10 , 2013 , Pages 2182-2194 ; 09544062 (ISSN) ; Mondali, M ; Abedian, A ; Sharif University of Technology
2013
Abstract
A new analytical formulation is presented to study the steady-state creep in short fiber composites using complex variable method. In this new approach, both the fiber and matrix creep at low stresses and temperatures. To analyze the crept fiber, a plane stress model was used. Important novelties of the present analytical method are determination of displacement rates with proper boundary conditions in the crept fibers and also using the complex variable method in creep analyzing. It is noteworthy that the method can be useful to study the creep behavior in polymeric matrix composites due to their high capability of creep. Moreover, another significant application of the present method is to...
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) ; Naghdabadi, R ; Sharif University of Technology
Department of Scientific Computing, Florida State University
2008
Abstract
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...
Compressive modulus and deformation mechanisms of 3DG foams: Experimental investigation and multiscale modeling
, Article Nanotechnology ; Volume 32, Issue 48 , 2021 ; 09574484 (ISSN) ; Adibnazari, S ; Del Monte, F ; Gutiérrez, M. C ; Sharif University of Technology
IOP Publishing Ltd
2021
Abstract
Due to the wide applications of three-dimensional graphene (3DG) foam in bio-sensors, stretchable electronics, and conductive polymer composites, predicting its mechanical behavior is of paramount importance. In this paper, a novel multiscale finite element model is proposed to predict the compressive modulus of 3DG foams with various densities. It considers the effects of pore size and structure and the thickness of graphene walls on 3DG foams' overall behavior. According to the scanning electron microscope images, a unit cell is selected in the microscale step to represent the incidental arrangement of graphene sheets in 3DG foams. After derivation of equivalent elastic constants of the...
Construction of New Polymer Electrolyte Based on PVDF-HFP, Plasticizer DMA AndSiO2nano-particles with High Ionic Conductivity for Lithium Batteries
, M.Sc. Thesis Sharif University of Technology ; Baghalha, Morteza (Supervisor) ; Khorasheh, Farhad (Supervisor)
Abstract
Polymer electrolytes are most frequently used electrolytes especially in lithium ion batteries. The gel-polymer and polymer-ceramic electrolytes were synthesized using DMA plasticizer, LiClO4, and SiO2 ceramic Nano fillers through coating method. EIS, FTIR, XRD, SEM, and TGA analyses were carried out on electrolytes. The optimum amount of perchlorate and polymer was obtained 0.5 M and 5% w/w, respectively. Also, the optimum amount of silica was obtained 2% w/w. the optimizations were carried out suing conductometry. The EIS analysis showed the ionic conductance of gel-polymer 1.8 mS.cm-1 while that of ceramic-polymer was obtained 2.8 mS.cm-1
Effect of chemical treatment of Teflon powder on the properties of polyamide 66/Teflon composites prepared by melt mixing
, Article Macromolecular Research ; Volume 19, Issue 6 , June , 2011 , Pages 613-621 ; 15985032 (ISSN) ; Gholamalipour, S ; Sharif University of Technology
2011
Abstract
The surface defluorination of Teflon in powdery form was performed using a chemical treatment. The reaction parameters including the reaction time, sodium, naphthalene concentrations were optimized using a Taguchi method to obtain maximum functionality on the particles surface. The surface functionality of the treated particles was analyzed by FTIR, energy dispersive X-ray analysis (EDX) and surface energy. Both treated (g-PTFE) and untreated (PTFE) Teflon were added to polyamide 66 (PA66) at various loadings up to 6 wt%. Mechanical, differential scanning calorimetry (DSC) and tribological analyses for different PA66/Teflon composites were carried out. The chemical treatment enhanced the...
The effect of transverse steel and FRP jacket confinement on mechanical properties of concrete cylinders: An experimental study
, Article ISEC 2011 - 6th International Structural Engineering and Construction Conference: Modern Methods and Advances in Structural Engineering and Construction ; 2011 , Pages 827-832 ; 9789810879204 (ISBN) ; Javid, Y ; Khosravi, H ; Yazdani S ; Cheung S. O ; Singh A ; Ghafoori N ; American Society of Civil Engineers (ASCE); Architectural Institute of Japan (AIJ); Chartered Institute of Building (CIOB); et al.; University of Nevada Las Vegas (UNLV), College of Engineering; Wayne State College of Engineering ; Sharif University of Technology
Abstract
This paper presents the results of an experimental study on the behavior of concrete cylinders externally wrapped with fiber-reinforced polymer (FRP) composites and internally reinforced with steel spirals. The experimental work was performed by testing 30 concrete cylinders (120 × 400mm2) subjected to pure compression to achieve the complete stress-strain curve. Test specimens were confined with various internal and external confinement ratios and different types of confining material such as steel, Carbon FRP (CFRP) and Glass FRP (GFRP). The compressive strength, corresponding strain and the complete stress-strain curve of the tested specimenswere indicated. The test results showthat the...
Acidic derivatives of melamine as template in copolymerization of aniline and metanilic acid
, Article Polymer - Plastics Technology and Engineering ; 2017 , Pages 1-10 ; 03602559 (ISSN) ; Najafi Moghadam, P ; Hashemi, M. M ; Sharif University of Technology
Abstract
In this paper, new polymer composites were synthesized by template copolymerization of aniline and metanilic acid in the presence of prepared melamine triacetic acid and poly(melamine-co-citric acid) as polyacids and dopants. The properties of the poly(aniline-co-metanilic acid) composites were studied by Fourier transform infrared, X-ray diffraction, scanning electron microscope, CV, and differential scanning calorimeter analysis. The four-point probe technique was used for evaluating the electrical conductivity of the composites. The scanning electron micrographs disclosed that the products had the morphology with agglomerated distorted spherical shapes with the average size of 40–50 nm....
Acidic derivatives of melamine as template in copolymerization of aniline and metanilic acid
, Article Polymer - Plastics Technology and Engineering ; Volume 57, Issue 10 , 2018 , Pages 965-974 ; 03602559 (ISSN) ; Najafi Moghadam, P ; Hashemi, M. M ; Sharif University of Technology
Taylor and Francis Inc
2018
Abstract
In this paper, new polymer composites were synthesized by template copolymerization of aniline and metanilic acid in the presence of prepared melamine triacetic acid and poly(melamine-co-citric acid) as polyacids and dopants. The properties of the poly(aniline-co-metanilic acid) composites were studied by Fourier transform infrared, X-ray diffraction, scanning electron microscope, CV, and differential scanning calorimeter analysis. The four-point probe technique was used for evaluating the electrical conductivity of the composites. The scanning electron micrographs disclosed that the products had the morphology with agglomerated distorted spherical shapes with the average size of 40–50 nm....
Study the effect of viscoelastic matrix model on the stability of CNT/polymer composites by multiscale modeling
, Article Polymer Composites ; Volume 30, Issue 11 , 2009 , Pages 1545-1551 ; 02728397 (ISSN) ; Naghdabadi, R ; Sharif University of Technology
2009
Abstract
In this article, a Molecular Structural Mechanics/Finite Element (MSM/FE) multiscale modeling of carbon nanotube/polymer composites with viscoelastic (VE) polymer matrix is introduced. The nanotube is modeled at the atomistic scale using structural molecular mechanics. The matrix deformation is analyzed by nonlinear finite element method considering VE behavior. The nanotube and matrix are assumed to be bonded by van der Waals interactions based on the Lennard-Jones potential at the interface. Using the MSM/FE multiscale model, we investigate the effect of carbon nanotube (CNT) on the improvement of mechanical stability of the nanocomposite. Also, the buckling behavior of these...
In pursuit of a replacement for conventional high-density polyethylene tubes in ground source heat pumps from their composites – a comparative study
, Article Geothermics ; Volume 87 , September , 2020 ; Fatehifar, M ; Ghasempour, R ; Noorollahi, Y ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Ground-source heat pumps, as the most environmentally friendly and energy-efficient air conditioning technology, suffer from a great required length of ground heat exchanger, partly arising from the low thermal conductivity of high-density polyethylene tubes commonly used in ground heat exchangers. In an attempt to find a replacement with an acceptable thermal conductivity for high-density polyethylene tubes, in this study, first, a comprehensive comparative study on fillers commonly used in thermally conductive polymer composites and resulting high-density polyethylene composites was conducted. Then, based on the advantages and disadvantages presented, an appropriate composite was selected...