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Practical techniques for improving the performance of polymeric membranes and processes for protein separation and purification
, Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 37, Issue 2 , February , 2018 , Pages 1-23 ; 10219986 (ISSN) ; Minooei, F ; Hosseini, S. S ; Sharif University of Technology
Iranian Journal of Chemistry and Chemical Engineering
2018
Abstract
Protein separation and purification technologies play an essential role in various industries including but not limited to pharmaceuticals, dairy as well as the food sector. Accordingly, a wide variety of techniques such as chromatography and electrophoresis have been developed and utilized extensively over the years for this purpose. Despite their widespread acceptance, conventional techniques still suffer from major limitations and complexities such as short lifetime, low productivity, high-pressure drop and difficulty in scale-up among others. Membrane separation processes have received significant attention in recent years as a promising alternative that can potentially overcome the...
Kinetic and morphological investigation on the magnesium ethoxide-based ziegler-natta catalyst for propylene polymerization using typical external donors
, Article Macromolecular Symposia ; Volume 285, Issue 1 , 2009 , Pages 52-57 ; 10221360 (ISSN) ; Ramezani Saadat Abadi, A ; Hiraoka, Y ; Kim, S. Y ; Taniike, T ; Terano, M ; Sharif University of Technology
2009
Abstract
Kinetic and morphological aspects of slurry propylene polymerization using a MgCl2-supported Ziegler-Natta catalyst synthesized from a Mg(OEt)2 precursor in the presence and absence of two different external donors are investigated. The kinetic profiles show similar trend in presence and absence of donors. The Mg(OEt)2-based catalyst show a mild activation and a long-standing activity with good replication of the catalyst particles. The results show that synthesized Mg(OEt)2-based Ziegler-Natta catalyst presents a highly stable polymerization activity and good replication due to the uniform Ti distribution all over the catalyst particles. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Synthesis, characterization, electrochemical and solvatochromic investigations of novel monomeric and polymeric vanadyl schiff-base complexes
, Article Journal of Coordination Chemistry ; Volume 60, Issue 9 , 2007 , Pages 973-983 ; 00958972 (ISSN) ; Bezaatpour, A ; Behzad, M ; Sharif University of Technology
2007
Abstract
This article describes the synthesis and characterization of oxovanadium(IV) complexes containing tetradentate Schiff-base ligands derived from condensation of ethylenediamine, meso-1,2-diphenyl-1,2-ethylenediamine, 1,2-orthophenylenediamine and 1,2-cyclohexanediamine with 5-bromo-3-nitro-2- hydroxybenzaldehyde. The novel VOL1:[VO(5-Br-3-NO2salen)], VOL2:[VO(5-Br-3-NO2saloph)] and VOL3:[VO(5-Br- 3-NO2salchxn)] complexes were obtained in orange polymeric form with (V=O) stretching bands at 878, 884 and 884 cm-1, respectively, but the VOL4 complex was obtained as a green monomer with (V=O) stretching band at 978 cm-1. The redox process in acetonitrile was reversible for VOL4 and E° was...
Modified carrageenan. 2. Hydrolyzed crosslinked κ -carrageenan-g-PAAm as a novel smart superabsorbent hydrogel with low salt sensitivity
, Article Journal of Biomaterials Science, Polymer Edition ; Volume 15, Issue 12 , 2004 , Pages 1499-1511 ; 09205063 (ISSN) ; Pourjavavdi, A ; Zohuriaan Mehr, M. J ; Sharif University of Technology
2004
Abstract
A novel pH-responsive superabsorbing hydrogel based on κ-carrageenan (κC) was prepared through polyacrylamide crosslinking grafting followed by alkaline hydrolysis. The hydrogel structure was confirmed using FT-IR spectroscopy. The hydrolysis conditions were systematically optimized to obtain a hydrogel with maximum swelling capacity. Thus, the reaction variables, including the hydrolysis time and temperature, concentration of sodium hydroxide, amount of hydrogel hydrolyzed and post-neutralization pH, were optimized. The swelling measurements of the hydrogels were conducted in 0.15 M aqueous solutions of LiCl, NaCl, KCl, CaCl2 and AlCl3. As observed for the hydrolyzed hydrogel (H-carragPAM),...
Modified CMC. 2. Novel carboxymethylcellulose-based poly(amidoxime) chelating resin with high metal sorption capacity
, Article Reactive and Functional Polymers ; Volume 61, Issue 1 , 2004 , Pages 23-31 ; 13815148 (ISSN) ; Pourjavadi, A ; Salehi Rad, M ; Sharif University of Technology
2004
Abstract
Carboxymethylcellulose sodium salt (CMC) was doubly modified to prepare a novel poly(acrylamidoxime) chelating resin. Acrylonitrile was firstly graft polymerized onto CMC using cerium ammonium nitrate as an initiator. The polyacrylonitrile (PAN) grafted CMC was then amidoximized via treatment with hydroxylamine to prepare the ion exchange resin. The sorption capacity of the resin towards bivalent metal ions was evaluated while varying the pH, the loading of the PAN and the initial metal ion concentration. The adsorption kinetics were investigated for the cupric ion. The chelating resin exhibited very high metal sorption capacity in comparison with either synthetic or polysaccharide-based...
Constrained model predictive control of MMA polymerization reactor based on genetic algorithm optimization
, Article Proceedings of 2003 IEEE Conference on Control Applications, Istanbul, 23 June 2003 through 25 June 2003 ; Volume 1 , 2003 , Pages 464-469 ; Solgi, R ; Abbaszadeh, M ; Sharif University of Technology
2003
Abstract
Control of MMA polymerization batch reactor has intensively investigated. The nonlinear and time varying behavior of the system makes its control a challenging task. MPC algorithm is enjoying an increasing application for control of chemical processes. A sequential linearized model based predictive controller based on the DMC algorithm was designed to control the temperature of a batch MMA polymerization reactor. A genetic algorithm (GA) is suggested to optimize the cost function of DMC. The controller performance was studied via simulation. The controller performance in tracking the profile, noise and disturbances rejection is very good
Microwave-induced Cannizzaro reaction over neutral γ-alumina as a polymeric catalyst
, Article Reactive and Functional Polymers ; Volume 51, Issue 1 , 2002 , Pages 49-53 ; 13815148 (ISSN) ; Soleimanzadeh, B ; Marandi, G. B ; Sharif University of Technology
2002
Abstract
Microwave induced Cannizzaro reaction, which was performed in presence of neutral γ-alumina as a polymeric catalyst, was discussed. Cannizzaro reaction was carried out on alumina surface and other unknown products were also obtained. Solvent extraction method was utilized to isolate mild and selective benzyl alcohol and carboxylic acids
Diffusional release of a dispersed solute from a cylindrical polymeric matrix into an infinite external volume
, Article Applied Mathematics and Computation ; Volume 259 , May , 2015 , Pages 676-685 ; 00963003 (ISSN) ; Abdekhodaie, M. J ; Sharif University of Technology
Elsevier Inc
2015
Abstract
Numerical and analytical exact solutions of diffusional release from a cylindrical polymeric matrix into an infinite medium have been developed in which the initial solute loading (A) is greater than solubility limit (Cs). Also, the effects of boundary layers on the drug release rate have been studied. The numerical solution is valid for any initial drug loading whereas analytical solution can be used for high values of drug loading. Comparisons have been made between numerical and analytical exact solutions in upper and lower bounds (A/Cs蠑1 and A/Cs→1) and previously presented approximate solution. The presented results validate the proposed numerical solution
Dynamic simulation and open-loop control of particle size distribution of styrene emulsion polymerization
, Article Iranian Polymer Journal (English Edition) ; Volume 15, Issue 11 , 2006 , Pages 901-911 ; 10261265 (ISSN) ; Shahrokhi, M ; Sharif University of Technology
2006
Abstract
Particle size distribution determines the major end-use properties of latex produced by emulsion. Therefore simulation and control of particle size distribution are important in emulsion polymerization. The investigated system is styrene polymerization. The model for determination of particle size distribution is based on population balance, accounting for nucleation and growth phenomena. The population balance equation (PBE) is discretized respect to particle radius. The ordinary differential equations obtained from discretization of PBE, initiator and monomers mass balances and algebraic thermodynamic equations are solved simultaneously via MATLAB programme. The accuracy of the model has...
A stacked neural network approach for yield prediction of propylene polymerization
, Article Journal of Applied Polymer Science ; Volume 116, Issue 3 , May , 2010 , Pages 1237-1246 ; 00218995 (ISSN) ; Shahsavan, H ; Bolouri, O ; Taranejoo, S ; Goodarzi, V ; Torabi Angaji, M ; Sharif University of Technology
2010
Abstract
Prediction of reaction yield as the most important characteristic process of a slurry polymerization industrial process of propylene has been carried out. Stacked neural network as an effective method for modeling of inherently complex and nonlinear systems-espe-cially a system with a limited number of experimental data points-was chosen for yield prediction. Also, effect of operational parameters on propylene polymerization yield was modeled by the use of this method. The catalyst system was Mg(OEt)2/DIBP/TiCl 4/PTES/AlEt3, where Mg(OEt)2, DIBP (diisobutyl phthalate), TiCl4, PTES (phenyl triethoxy silane), and triethyl aluminum (AlEt3) (TEAl) were employed as support, internal electron...
In situ preparation and property investigation of polypropylene/fumed silica nanocomposites
, Article Polymer Composites ; Vol. 35, issue. 1 , January , 2014 , pp. 37-44 ; ISSN: 02728397 ; Ahmad Ramazani, S. A ; Jafariesfad, N ; Sharif University of Technology
Abstract
We present the preparation of polypropylene (PP)/fumed silica (FS) nanocomposites via in situ polymerization in this article. The approach includes preparation and utilization of a bisupported Ziegler-Natta catalytic system in which magnesium ethoxide and FS are used as conjugate supports of the catalyst. Catalyst preparation and polymerization processes are carried out in the slurry phase and under argon atmosphere. Scanning electron microscopy images show a good dispersion of the FS throughout the PP matrix. Results from differential scanning calorimetry reveal that the crystallization temperature of prepared nanocomposites increases by increasing FS loading. Also, crystal content of...
Preparation and characterization of UHMWPE/graphene nanocomposites using bi-supported ziegler-natta polymerization
, Article International Journal of Polymeric Materials and Polymeric Biomaterials ; Vol. 63, issue. 16 , 2014 , p. 815-819 ; Ramazani, S. A ; Sharif University of Technology
Abstract
Ultrahigh-molecular-weight polyethylene (UHMWPE)/graphene nanocomposites with molecular weights as high as 3 × 106 g/mol were prepared via in situ polymerization using a bi-supported Ziegler-Natta catalytic system. Effects of [Al]/[Ti] molar ratio, temperature, monomer pressure, and polymerization time on productivity of the catalyst have been investigated. Increasing [Al]/[Ti] molar ratio from 128 to 320, increased productivity from 1667 g PE/mmol Ti.h to maximum value which was 2420 g PE/mmol Ti.h. Further [Al]/[Ti] ratio decreased the productivity. Reaction temperature effect investigation reveals that the optimal activity was obtained at 60°C. the polymerization productivity increases...
Novel carbon-nanotube-based organogels as candidates for oil recovery
, Article Polymer International ; Volume 62, Issue 2 , JUN , 2013 , Pages 179-183 ; 09598103 (ISSN) ; Doulabi, M ; Soleyman, R ; Sharif University of Technology
2013
Abstract
A simple method for synthesis of novel organogels based on multiwalled carbon nanotubes (MWCNTs) is reported. Three classes of organogels were synthesized by crosslinking polymerization of dodecyl methacrylate with various weight percentages of 1,4-butanediol dimethacrylate, vinyl-group-modified MWCNTs or pristine MWCNTs in the presence of 2,2-azoisobutyronitrile as initiator. In this reaction, the carbon nanotubes (CNTs) served simultaneously as an adsorbent, a comonomer and a crosslinking agent. The oil-absorbent containing CNTs showed much higher swelling capacity in oil and organic solvents compared with that without CNTs. Therefore, CNT-based organogels can be introduced as a promising...
Use of a novel initiator for synthesis of amino-end functionalized polystyrene (NH 2-PS) by atom transfer radical polymerization
, Article Journal of Polymer Research ; Volume 19, Issue 1 , January , 2012 ; 10229760 (ISSN) ; Seidi, F ; Jahromi, P. E ; Salimi, H ; Roshan, S ; Najafi, A ; Bruns, N ; Sharif University of Technology
2012
Abstract
Here we report a versatile new method for endfunctionalizing polystyrene. In order to produce polystyrene with an amino end group, 2-(3-bromo-3- phenylpropyl) isoindoline-1,3-dione was synthesized and used as a novel initiator for ATRP. After ATRP polymerization, tri-n-butyltin hydride ((n-Bu) 3SnH) reductively replace existing halogens on polymer chains by hydrogen. Finally, the phthaloyl groups on polymer backbone were cleaved by treatment with hydrazine yielding amino terminated polystyrene. A polymer with M n≈10,350 and M w/M n01.17 was obtained. Therefore, this method allows the preparation of amino end functionalized polystyrene of narrow polydispersity with complete degree of...
Synthesis and characterization of polyamide membrane for the separation of acetic acid from water using RO process
, Article Membrane Water Treatment ; Volume 8, Issue 4 , 2017 , Pages 323-336 ; 20058624 (ISSN) ; Mousavi, S. A ; Mortazavi, S. S ; Sadeghi, M ; Bastani, D ; Sharif University of Technology
Techno Press
2017
Abstract
The main challenge in many applications of acetic acid is acid dehydration and its recovery from wastewater streams. Therefore, the performance of polyamide thin film composite is evaluated to separate acetic acid from water. To reach this goal, the formation of polyamide layer on polysulfone support membrane was investigated via interfacial polymerization (IP) of meta-phenylenediamine (MPD) in water with trimesoyl chloride (TMC) in hexane. Also, the effect of synthesis conditions, such as concentration of monomers and curing temperature on separation of acetic acid from water were investigated by reverse osmosis process. Moreover, the separation mechanism was discussed. The solute...
Synthesis of SBR/PMMA core/shell latices: the role of initiator and surfactant on particle morphology and instability performance
, Article Journal of Applied Polymer Science ; Volume 105, Issue 3 , 2007 , Pages 1412-1419 ; 00218995 (ISSN) ; Mohammadi, N ; Bagheri, R ; Sharif University of Technology
2007
Abstract
Poly(butadiene-stat-styrene)/poly(methylmetacrylate), SBR/PMMA, structural latices were synthesized by using equal moles of different kinds of surfactants: anionic, nonionic, and anionic/nonionic mixture in a two-stage emulsion polymerization. The results indicate that the application of anionic surfactants for the first stage, accompanying sodium persulfate initiator, KPS, for both stages led to core/shell and raspberry morphologies depended upon the hydrophilic lipophilic balance (HLB) of the surfactant. On the other hand, a core/shell structure was observed for structural latices which were synthesized via application of nonionic or anionic/non-ionic mixed surfactants along with...
Preparation of poly (acrylic acid) microgels by alcohol type cross-linkers and a comparison with other cross-linking methods
, Article Polymer Bulletin ; 2021 ; 01700839 (ISSN) ; Bouhendi, H ; Keshavarzi, N ; Mahmoudi, M ; Pourjavadi, A ; Ghiass, M ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
Herein, poly (acrylic acid) (PAA) microgels were synthesized via alcohol type cross-linked by a free radical precipitation polymerization approach. At the first time, 1,6-hexanediol (1–6 diol), trimethylolpropane (TMP), and pentaerythritol (PEN) were selected as multifunctional cross- linking agent to synthesize cross-linked poly(acrylic acid) microgels. Alcohol type cross-linking agents can connect the PAA chains. The cross-linking reaction takes place due to reaction between hydroxyl groups of various cross-linkers and carboxyl groups of PAA chains. All of the hydroxyl groups do not participate in the reaction with acid groups of polymer chains through the polymerization stage; therefore,...
Multiple Model Predictive Control of Methyl Methacrylate/Vinyl Acetate Synthesis Reactor
, M.Sc. Thesis Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor)
Abstract
The purpose of this study is the implementation of multi-model predictive control (MMPC) approach for the co-polymerization system of methyl methacrylate - vinyl acetate. Simpler development of local models and controllers and also convenience of understanding the model and controller structure are the main reasons for using this approach. In the first step, RGA analysis has been used for pairing input and output variables. Then the performance of PI controller on the system has been investigated. For designing model predictive controller (MPC) the nonlinear model has been linearized at operational point and the controller has been designed in MPC toolbox of MATLAB software R2013a. In the...
Study of the Poly (vinyl acetate)/SiO2 Nanocomposites Produced by in Situ Polymerization
, M.Sc. Thesis Sharif University of Technology ; Ramazani Saadat Abadi, Ahmad (Supervisor)
Abstract
The main object of this thesis is synthesizing poly(vinyl acetate)/ colloidal silica nanocomposites via emulsion and in-situ polymerization methods. At the first, nanocomposites were produced in the presence of poly(vinyl alcohol) as the protective colloid, ammonium persulphate as the initiator and sodium bicarbonate as the buffer in an aqueous solution. Then, structural, thermal, rheological, mechanical and surface properties of produced nanocomposites with various colloidal silica content (0.5 %, 1 %, 1.5 %) were evaluated by DLS, FTIR, SEM-EDS, DSC, TGA, dynamic and steady rheological tests, tensile and shear mechanical tests, AFM and static water contact angle. The particle size of...
Synthesis and Characterization of Polymer Nanofibers Modified by Using of Radiated Grafting for Adsorption of Molybdenum Ions from Aqueous Solution
, M.Sc. Thesis Sharif University of Technology ; Outokesh, Mohammad (Supervisor) ; Asadollahzadeh, Mehdi (Supervisor) ; Torkaman, Rezvan (Co-Supervisor) ; Torab Mostaedi, Meysam (Co-Supervisor)
Abstract
Molybdenum is one of the important elements of the intermediary metal with atomic number 42, which is used in various industries, but among the important uses of this metal in the nuclear industry, we can mention the presence of this element in the production of yellow cake as an impurity and also as a precursor for the production of radiopharmaceuticals. It is one of the impurities that remain in all stages of yellow cake production along with uranium, and the high presence of this element causes the centrifuges to become unbalanced during the injection of "U" "F" _"6" gas, and on the other hand, technetium, the main ingredient in the production of radiopharmaceuticals, It comes from the...