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filled-polymers
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Investigation of Nanoparticles Effects on Rheology of Particulate Filled Polymeric Systems
, M.Sc. Thesis Sharif University of Technology ; Ramazani Saadatabadi, Ahmad (Supervisor) ; Haghgoo, Majid (Co-Supervisor)
Abstract
In this study, the effect of molybdenum disulfide nanosheets on the rheological behavior of suspensions was investigated using a polyethylene glycol matrix and glass grain fillers with a particle distribution of 60 to 103 microns. Crude molybdenum disulfide was obtained by single-layer and multilayered molybdenum disulfide nanosheets with thicknesses between 50 and 100 nm using acid, oxidation and heat shock methods. This claim was verified by various tests such as FT-IR, FESEM,EDS, TEM, DLS, XRD and so on. Subsequently, using 10 to 40% volumetric glass beads were prepared from the sample matrix. Stirring and ultrasonic, rheological behavior of these suspensions were investigated using...
Vulcanization kinetics and reversion behavior of natural rubber/styrene-butadiene rubber blend filled with nanodiamond - The role of sulfur curing system
, Article European Polymer Journal ; Volume 81 , 2016 , Pages 98-113 ; 00143057 (ISSN) ; Shojaei, A ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
The effect of nanodiamond (ND) particles on the network structure and vulcanization kinetics of natural rubber (NR)/styrene-butadiene rubber (SBR) blend vulcanized by three different curing systems, namely conventional (CV), semi-efficient (SEV) and efficient (EV), was investigated. The filler dispersion, crosslink density, curing kinetics and reversion behavior were fully studied. The state of ND dispersion in the rubber matrix was investigated by the field emission scanning electron microscope (FESEM). Swelling experiments and tensile tests exhibited that upon incorporation of ND crosslink density of NR/SBR blend was enhanced significantly due to the large surface area of nano filler...
Unified modeling and experimental realization of electrical and thermal percolation in polymer composites
, Article Applied Physics Reviews ; Volume 9, Issue 4 , 2022 ; 19319401 (ISSN) ; Arabshahi, Z. S ; Saberi, A. A ; Moshfegh, A. Z ; Sharif University of Technology
American Institute of Physics Inc
2022
Abstract
Correlations between electrical and thermal conduction in polymer composites are blurred due to the complex contribution of charge and heat carriers at the nanoscale junctions of filler particles. Conflicting reports on the lack or existence of thermal percolation in polymer composites have made it the subject of great controversy for decades. Here, we develop a generalized percolation framework that describes both electrical and thermal conductivity within a remarkably wide range of filler-to-matrix conductivity ratios (Y f / Y m), covering 20 orders of magnitude. Our unified theory provides a genuine classification of electrical conductivity with typical Y f / Y m ≥ 10 10 as...
Tire tread performance of silica-filled SBR/BR rubber composites incorporated with nanodiamond and nanodiamond/nano-SiO2 hybrid nanoparticle
, Article Diamond and Related Materials ; Volume 126 , 2022 ; 09259635 (ISSN) ; Momenilandi, M ; Shojaei, A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
In the present research, the influence of nanodiamond (ND) and a physical hybrid of ND and fumed nano-SiO2 were investigated on the performance of a typical tire tread compound. The styrene-butadiene rubber (SBR) and cis-butadiene rubber (BR) blend filled with a commercial grade highly dispersive silica at 70 phr loading were used as typical tire tread compound. ND was substituted partially with silica at two different concentrations of 5 and 10phr. Meanwhile, 5 phr of ND/nano-SiO2 hybrids with the weight ratio of 2.5/2.5 and 1/4 were substituted with silica. ND-Filled compounds exhibit increased scorch and cure time compared to controls. Improvement in different characteristics of the...
Thermophysical and rheological behavior of polystyrene/silica nanocomposites: Investigation of nanoparticle content
, Article Materials and Design ; Volume 32, Issue 8-9 , 2011 , Pages 4537-4542 ; 02641275 (ISSN) ; Omaraei, I.A ; Abadyan, M ; Mortezaei, M ; Yousefi, N ; Sharif University of Technology
Abstract
In this work, solvent blending in combination with extruding are applied to provide polystyrene/silica nanocomposite specimens. Transmission electron microscope (TEM) and scanning electron microscope (SEM) show same nanoparticle dispersion in PS matrix in low to high filler loadings. Differential scanning calorimetry (DSC), dynamic mechanical thermal analyzer (DMTA) and thermogravimetric analyzer (TGA) were used to study the thermophysical characteristic of the nanocomposites in solid state. In addition, the melt state rheological behavior of the samples was investigated under constant and zero shear rates. Interestingly, different behaviors were detected in nanocomposites in low and high...
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...
The effects of elevated temperatures on the performance of concrete-filled pultruded GFRP tubular columns
, Article Thin-Walled Structures ; Volume 169 , 2021 ; 02638231 (ISSN) ; Khaloo, A ; Azizmohammadi, M ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Usage of concrete-filled pultruded glass fiber-reinforced polymer (GFRP) tubes (CFPGT) as columns can increase the service life of structures. However, marine structures such as oil platforms are always prone to fire because of the low resistance to the elevated temperatures. The purpose of this investigation is to evaluate the effects of concrete core strength (30 and 60 MPa), and exposure temperature (25, 100, 200, 300, and 400 °C) and time (60 and 120 min) on the compressive and bond behavior of CFPGTs. The properties of unexposed and exposed concrete core, pultruded GFRP hollow tubes, and CFPGTs were determined via compressive and disk-split tests. Also, the push-out test was used to...
Synergistic effect of polyindole decoration on bismuth neodymium ferrite powder for achieving wideband microwave absorber
, Article Ceramics International ; Volume 48, Issue 17 , 2022 , Pages 25049-25055 ; 02728842 (ISSN) ; Dong, S ; Mehrez, S ; Niaz Akhtar, M ; Tra Giang, H ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Recently, composite materials with outstanding absorption properties, like extraordinary absorbing capability, light weight, and thin in size, are required to solve the challenges of electromagnetic pollution. In addition, most of the work is based on the optimization of absorber material structure, and microstructure. In the current work, we improved the reflection loss feature of Bi0.5Nd0.5FeO3 nanopowders via decoration with polyindole polymer by tuning the filler loading of the nanocomposite in the matrix. XRD, UV–Vis, XPS, and FESEM were used to determine the physicochemical features of the as-prepared nanocomposite. The minimum RL was lowered further with the increasing filler loading...
Silane functionalization of nanodiamond for polymer nanocomposites-effect of degree of silanization
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 506 , 2016 , Pages 254-263 ; 09277757 (ISSN) ; Shojaei, A ; Sharif University of Technology
Elsevier B.V
2016
Abstract
The silanization of nanodiamond (ND) was successfully carried out by using the esterification reaction of hydrolyzed vinyltrimethoxysilane (VTS) in alcoholic solution. The surface carboxylic group of ND was first enhanced by thermal oxidation to increase the degree of esterification reaction. The extent of silane functionalization of ND was controlled by varying the weight ratio of VTS and oxidized ND (oxND), from 2:1 to 10:1 (w/w) in the functionalization reaction medium. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) revealed that the highest degree of silanization occurred at VTS/oxND of 5:1 (w/w), while more silane concentrations resulted in...
Role of different compatibilizing approaches on the microstructure and mechanical properties of polypropylene/talc composites
, Article AIP Conference Proceedings ; Vol. 1593, issue , 15- 19 July , 2014 , pp. 428-431 ; ISSN: 0094243X ; Bagheri, R ; Sharif University of Technology
Abstract
Since in a highly filled polymer, a major problem arises from non-uniformity of properties due to the poor dispersion of filler, the application of coupling agents have been directed to overcome this problem and also to enhance the mechanical performance of the composites by improving the adhesion at the interface. In this study, a comparison between two major coupling approaches is conducted: 1) Using PPgMA as a kind of compatibilizer which changes the nature of the matrix, 2) Using titanate coupling agent which takes action at the interface and reacts with hydroxyl groups at the inorganic filler surface, resulting in the formation of monomolecular layer on the inorganic surface to increase...
Reinforcing mechanisms of carbon nanotubes and high structure carbon black in natural rubber/styrene-butadiene rubber blend prepared by mechanical mixing-effect of bound rubber
, Article Polymer International ; Volume 64, Issue 11 , July , 2015 , Pages 1627-1638 ; 09598103 (ISSN) ; Shojaei, A ; Sharif University of Technology
John Wiley and Sons Ltd
2015
Abstract
The reinforcing effect of high structure carbon black (HSCB) and multi-walled carbon nanotubes (MWCNTs) on natural rubber/styrene-butadiene rubber blend processed using mechanical mixing was comparatively investigated. In-depth analysis by dynamic mechanical analysis, the Eggers-Schummer model and Medalia's relationship showed that HSCB aggregates provided large internal pores leading to significant immobilized macromolecules in filled rubber. Additionally, a tubular immobilized rubber layer with a thickness of 8nm was estimated for the rubber/MWCNT system based on dynamic mechanical analysis data. The mechanical performance of the HSCB filled blend was higher than that of the MWCNT filled...
Performance of polypropylene fiber reinforced concrete-filled UPVC tube columns under axial compression
, Article Construction and Building Materials ; Volume 231 , 20 January , 2020 ; Khaloo, A ; Borhani, M. H ; Tale Masoule, M. S ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
This paper aims to study the behavior of UPVC-confined columns reinforced with polypropylene fibers under axial compression. A sum of 42 column specimens has been tested, including 18 Unconfined Concrete Cylinders (UCC) and 24 confined Concrete-Filled UPVC Tube (CFUT) specimens. To investigate the sensitivity of these columns to various parameters, different levels of material volumes have been used, which include two concrete strengths of 40 and 50 MPa, two tube grades of PN6 and PN10, and three polypropylene fiber content of 0, 1 and 3 kg/m3 of the concrete mixture. The influence of each variable on the ultimate strength, ductility and confinement effectiveness of the specimens have been...
Modeling of stiffening and strengthening in nano-layered silicate/epoxy
, Article International Journal of Engineering, Transactions A: Basics ; Volume 30, Issue 1 , 2017 , Pages 93-100 ; 17281431 (ISSN) ; Pearson, R. A ; Bagheri, R ; Sharif University of Technology
Abstract
The aim of this paper is to investigate adhesion property between nano-layered filler and the polymer matrix using a combination of experimental and micromechanical models as well as the changes in yield strength and stiffness of a layered silicate-filled epoxy nanocomposite. The results indicate that addition of intercalated layered silicate particles increased Young's modulus and yield strength of the epoxy resin, although the increases in stiffness and yield strength are modest, 30% and 4%, respectively. In addition, experimental results were compared with predictive stiffening and strengthening models. The rule of mixtures provides an upper bound for the modulus in these materials, while...
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...
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...
https://www.sciencedirect.com/science/article/abs/pii/S0032386122006103
, Article Polymer ; Volume 255 , 2022 ; 00323861 (ISSN) ; Shojaei, A ; Salkhi Khasraghi, S ; Karimzad Ghavidel, A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Present work illustrated that the performance of ultrafine silica (Si) particles was improved considerably by rational hybridization with nanodiamond (ND). For this, Si@ND hybrid particles synthesized by chemical hybridization were incorporated into styrene-butadiene rubber (SBR) up to 10 phr. Scanning electron microscopy revealed coarse flower-like clusters for Si@ND nanohybrids, while Si exhibited rigid agglomerates in SBR. Comparing with physical hybrid (Si&ND) and single Si particles, it was revealed that chemical hybrids synergistically improved tensile properties, like 100% and 135% improvements in tensile strength and elongation at break, respectively. Dynamic mechanical analysis of...
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) ; Mirjavadi, S. S ; Salem Hamouda, A. M ; Makki, H ; Sharif University of Technology
Wiley-VCH Verlag
2017
Abstract
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...
Green composites in bone tissue engineering
, Article Emergent Materials ; Volume 5, Issue 3 , 2022 , Pages 603-620 ; 25225731 (ISSN) ; Vahabi, H ; Rabiee, N ; Rabiee, M ; Bagherzadeh, M ; Saeb, M. R ; Sharif University of Technology
Springer Nature
2022
Abstract
Natural and biodegradable polymers are of particular interest as green sources with low-cost and environmentally friendly features, and have been widely used for polymer composite development. The term “Green Composites” refers to polymer/filler systems in which polymer, filler, or sometimes both components are green in view of sources from which they are yielded or their biodegradability. Natural fibers obtained from plants, animals, and/or geological processes are a big class of green sources widely applied in green composite development. There has also been continued research on recycling of green composite as well as developing hybrid systems for advanced applications. In view of their...
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) ; Farzi, G ; Kalaee, M. R ; Zabihpoor, M ; Sharif University of Technology
2011
Abstract
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...
Enhanced microwave absorption performance of BiFeO3 nanopowders coated with Polyindole-PANI co-polymer in ku band frequency
, Article Journal of Magnetism and Magnetic Materials ; Volume 560 , 2022 ; 03048853 (ISSN) ; Alnujaie, A ; Tan Hoi, H ; Tra Giang, H ; Niaz Akhtar, M ; Sharif University of Technology
Elsevier B.V
2022
Abstract
It's still a significant difficulty to find microwave absorbers that have outstanding microwave dissipation performance in hostile environments. Herein, the core–shell structure of polyindole-PANI co-polymer@BiFeO3 nanocomposite is successfully prepared via in-situ polymerization method. The introduction of a co-polymer shell on the surface of magnetic BiFeO3 nanoparticles considerably tuned the attenuation constant and impedance matching characteristics. The electromagnetic characteristics and microwave absorption feature of the polyindole-PANI co-polymer@BiFeO3 nanocomposites may be found to be influenced by filler loading content regulation. The sample containing 40 wt% of polyindole-PANI...