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thermal-gravimetric-analysis
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Thermal Degradation and Kinetic Analysis of Polyethylene/Carbon Nanotube Nanocomposites Prepared via in Situ Polymerization
, M.Sc. Thesis Sharif University of Technology ; Ramazani Saadatabadi, Ahmad (Supervisor) ; Khorasheh, Farhad (Supervisor)
Abstract
In the preparation of nanocomposites, the multi-walled carbon nanotubes (MWCNTs) functionalized by hydroxyl groups were used. Subsequently, the polyethylene/multi-walled carbon nanotube (PE/MWCNTs) nanocomposites were prepared via in situ polymerization technique. In this study, effect of MWCNTs on the thermal degradation of these PE/MWCNT nanocomposites was investigated; the thermal degradations of pure PE and PE nanocomposites with different concentrations of nanotubes (0.5, 1.5, 3.5 wt %) have been studied by using thermal gravimetric analysis (TGA). Samples were heated to 700˚C at different heating rates (5, 10, 15, and 20˚C/min). TGA was used to investigate the effect of the MWCNTs on...
Kinetic Investigation of the Thermal Treatment of E-Waste with Particular Emphasis on Printed Circuit Boards (PCBs)
, M.Sc. Thesis Sharif University of Technology ; Fotovat, Farzam (Supervisor)
Abstract
In this study, pyrolysis features and corresponding kinetic behavior of non-metallic fractions of the paper-laminated phenol resin printed circuit boards (P-PCB) and fiberglass-reinforced epoxy resin printed circuit boards (E-PCB) were investigated by the use of simultaneous thermogravimetric analysis (TGA/DTG). The kinetic parameters of the P-PCB abs E-PCB during pyrolysis process were estimated from the experimental data by means of three iso-conversional kinetic models, including Friedman, Flynn-Wall-Ozawa (FWO), and Kissinger-Akahira-Sunose (KAS) methods. The activation energy range obtained for P-PCB and E-PCB utilizing the Friedman method was within 117–594.1 and 88.42-295.3 kJ.mol-1,...
Optimization of Morphology in Order to Produce Polypropylene Antistatic Fiber Containing Polyaniline
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Reza (Supervisor)
Abstract
In this study, the synthesis conditions of polyaniline were optimized in order to produce a blend based on polypropylene (PP) containing polyaniline (PANI) with the electrical conductivity in the antistatic range. A form of PANI that has adequate electrical conductivity and thermal stability, which is suitable for melt-mixing and melt-spinning conditions, was synthesized. Thermal stability and electrical conductivity of polyaniline were investigated by thermal gravimetric analysis (TGA), differential calorimetric analysis (DSC) and high-temperature electrical conductivity. It was found that the synthesized PANI has required thermal stability and electrical conductivity (106 ohm.cm) at the...
Fabrication and evaluation of nanocomposite membranes of polyethersulfone/α-alumina for hydrogen separation
, Article Iranian Polymer Journal (English Edition) ; Volume 24, Issue 3 , 2015 , Pages 171-183 ; 10261265 (ISSN) ; Rashidzadeh, M ; Safekordi, A ; Khanbabaei, G ; Sharif University of Technology
Springer-Verlag London Ltd
2015
Abstract
In this study, polyethersulfone (PES)-based nanocomposite membranes with the incorporation of inorganic filler of α-alumina were prepared via thermal phase inversion method. The fabricated flat sheet-mixed matrix membranes were characterized using X-ray diffraction, thermal gravimetric analysis, differential scanning calorimetry, scanning electron microscopy, and atomic force microscope analysis, and the permeation tests were performed for hydrogen, nitrogen and carbon dioxide. Also prepared α-alumina particles were identified by X-ray diffraction and the surface area, total pore volume and average pore diameter of particles were measured with a high-speed gas-sorption analyzer. The...
Performance of silver nanoparticle fixed on magnetic iron nanoparticles (Fe3O4−Ag) in water disinfection
, Article Micro and Nano Letters ; Volume 13, Issue 4 , April , 2018 , Pages 436-441 ; 17500443 (ISSN) ; Hassani, A. H ; Ahmad Panahi, H ; Borghei, M ; Sharif University of Technology
Institution of Engineering and Technology
2018
Abstract
Microbial contamination poses a serious threat to human health. The evaluation of alternative systems and their reliability for the treatment of water is essential. In this work, a new method for the deposit of more silver nanoparticles (AgNPs) on the external surface of Fe3O4 nanoparticles is presented. Fe3O4 nanoparticles were synthesised by chemical co-precipitation and were modified in two stages using 3-mercaptopropyl trimethoxysilane and grafting allyl glycidyl ether and N, N-dimethylacrylamide. Then, AgNPs were loaded onto the modified Fe3O4 to be used for water disinfection. The resulting nanoparticles were characterised by transmission electron microscopy, X-ray powder diffraction,...
Mechanical, rheological and oxygen barrier properties of ethylene vinyl acetate/diamond nanocomposites for packaging applications
, Article Diamond and Related Materials ; Volume 99 , 2019 ; 09259635 (ISSN) ; Ramazani S. A., A ; Haddadi, S. A ; Kheradmand, A ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
In this work, the effects of the surface-modified nanodiamond particles (NDs) on the barrier, rheological, mechanical and thermal properties of ethylene vinyl acetate (EVA) composites for the packaging applications were investigated. Fourier transform infrared spectroscopy, as well as thermal gravimetric analysis were employed to study the grafting of vinyltriethoxy silane (VTS) on the surface of NDs. Afterwards, EVA samples containing 0, 0.1, 0.5, 1, 1.5 and 2 wt% of surface-modified NDs were prepared by a two-stage process including the solution and injection processes. In order to evaluate the physicochemical, rheological, mechanical and thermal properties of the EVA/NDs samples, field...
Core-sheath gelatin based electrospun nanofibers for dual delivery release of biomolecules and therapeutics
, Article Materials Science and Engineering C ; Volume 108 , 2020 ; Lotfi, R ; Tamjid, E ; Shokrgozar, M. A ; Simchi, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Coaxial electrospinning with the ability to use simultaneously two separate solvents provides a promising strategy for drug delivery. Nevertheless, controlled release of hydrophilic and sensitive therapeutics from slow biodegradable polymers is still challenging. To address this gap, we fabricated core-sheath fibers for dual delivery of lysozyme, as a model protein, and phenytoin sodium as a small therapeutic molecule. The sheath was processed by a gelatin solution while the core fibers were fabricated from an aqueous gelatin/PVA solution. Microstructural studies by transmission and scanning electron microscopy reveal the formation of homogeneous core-sheath nanofibers with an outer and...
The effect of various acids treatment on the purification and electrochemical hydrogen storage of multi-walled carbon nanotubes
, Article Journal of Power Sources ; Volume 183, Issue 2 , 1 September , 2008 , Pages 539-543 ; 03787753 (ISSN) ; Mortazavi, S. Z ; Nozad Golikand, A ; Moshfegh, A. Z ; Mirershadi, S ; Sharif University of Technology
Elsevier
2008
Abstract
The effects of HCl, HNO3, H2SO4 and HF acids on the purification and the electrochemical hydrogen storage of multi-walled carbon nanotubes (MWCNTs) were studied. The MWCNTs were synthesized on Fe-Ni catalyst by thermal chemical vapor deposition method. The X-ray diffraction and thermal gravimetric analysis results indicated that the MWCNTs purified by HF acid had the highest impurities as compared with the other acids. The N2 adsorption results at 77 K indicated that all the samples were mainly mesoporous and the purified MWCNTs by HF acid had the highest surface area as compared with the other acids. The hydrogen storage capacities of the purified MWCNTs by the following acids were in...
Visible light photocatalytic activity of novel MWCNT-doped ZnO electrospun nanofibers
, Article Journal of Molecular Catalysis A: Chemical ; Volume 359 , 2012 , Pages 42-48 ; 13811169 (ISSN) ; Shivaee, H. A ; Zanetti, M ; Pourjavadi, A ; Moshfegh, A ; Sharif University of Technology
2012
Abstract
Multi wall carbon nanotube (MWCNT) doped ZnO nanofibers were fabricated by electrospinning for the first time. We have successfully demonstrated the photocatalytic activity of doped nanofibers under visible light. Scanning electron microscopy showed that the diameter of MWCNT-doped ZnO nanofibers varied from 120 to 300 nm without agglomeration of MWCNT. Fourier transform infrared spectroscopy and X-ray diffraction studies proved the formation of ZnO bond and wurtzite structure with smaller crystal size in doped nanofibers. Raman spectra demonstrated slight shift in bond position after nanofiber doping, indicating the chemical bond between MWCNT and ZnO. X-ray photoelectron spectroscopy...
A study on the effects of Fex/Niy/MgO(1-x-y) catalysts on the volumetric and electrochemical hydrogen storage of multi-walled carbon nanotubes
, Article International Journal of Hydrogen Energy ; Volume 35, Issue 1 , 2010 , Pages 231-237 ; 03603199 (ISSN) ; Mortazavi, S. Z ; Zaker Moshfegh, A ; Nozad Golikand, A ; Sharif University of Technology
Abstract
The effects of various ratios of Fe/Ni/MgO and growth temperatures on yield, diameter and quality of multi-walled carbon nanotubes (MWCNTs) were studied. Thermal gravimetric analysis (TGA) confirmed that the MWCNT yield depends on Fe/Ni ratio with the following order; Fe0.5 Ni0.5 > Fe > Fe0.75 Ni0.25 > Fe0.25 Ni0.75 > Ni. The results indicated that there is an optimum temperature (940 °C) for the MWCNT growth both from quality and quantity (yield) aspects as compared to other temperatures. Moreover, the changes on Fe/Ni to MgO ratio for the MWCNT growth revealed that Fe/Ni/MgO with the ratio of 17.5/17.5/65 had the highest quality and surface area as compared to the other ratios. The...
Enhanced electrochemical hydrogen storage by catalytic Fe-doped multi-walled carbon nanotubes synthesized by thermal chemical vapor deposition
, Article Journal of Power Sources ; Volume 188, Issue 2 , 2009 , Pages 404-410 ; 03787753 (ISSN) ; Mortazavi, S.Z ; Moshfegh, A.Z ; Golikand, A.N ; Amiri, M ; Sharif University of Technology
2009
Abstract
Hydrogen storage capacities of raw, oxidized, purified and Fe-doped multi-walled carbon nanotubes (MWCNTs) were studied by electrochemical method. Based on transmission electron microscopy and Raman spectroscopic data, thermal oxidation removed defective graphite shells at the outer walls of MWCNTs. The analysis results indicated that the acid treatment dissolved most of the catalysts and opened some tips of the MWCNTs. Thermal gravimetric analysis and differential scanning calorimetry results illustrated that by oxidation and purification of MWCNTs, the weight loss peak shifts toward a higher temperature. N2 adsorption isotherms of the purified and oxidized MWCNTs showed an increase in N2...