Search for: emulsion-polymerization
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    Preparation of conductive polyaniline/graphene nanocomposites via in situ emulsion polymerization and product characterization

    , Article Synthetic Metals ; Vol. 196 , 2014 , pp. 199-205 Baniasadi, H ; Ramazani, S. A ; Mashayekhan, S ; Ghaderinezhad, F ; Sharif University of Technology
    This work, which is a part of our ongoing studies on developing conductive scaffolds for nerve tissue engineering, reports synthesis of highly conductive binary-doped polyaniline nanoparticles and polyaniline/graphene nanocomposites. The samples were synthesized through chemical oxidation of aniline via in situ emulsion polymerization method in presence of hydrochloric acid and sodium dodecyl sulfate. Graphene nanosheets were also prepared via modified Hummer's method followed by chemical reduction using hydrazine monohydrate. Electrical conductivity measurements using a standard four-point probe technique with FTIR and UV-vis studies revealed that conductive binary-doped emeraldine salt... 

    Simulation and control of monomer conversion in a continuous emulsion polymerization reactor

    , Article IFAC Proceedings Volumes (IFAC-PapersOnline), 7 June 2015 through 10 June 2015 ; Volume 48, Issue 8 , 2015 , Pages 315-320 ; 14746670 (ISSN) Barazandegan, M ; Shahrokhi, M ; Abedini, H ; Vafa, E ; Guay, M ; Gopaluni, B ; Huang, B ; Findeisen, R ; Sharif University of Technology
    IFAC Secretariat  2015
    A detailed pseudo-bulk model has been used for prediction of conversion and particle size distribution (PSD) of vinyl acetate in a continuous emulsion polymerization reactor. Finite volume (FV) and moment techniques are applied for solving population balance equation under continuous operation. It is found that both methods can predict sustained oscillations in the monomer conversion, however the FV method matches the experimental data better than the moment method. The monomer conversion and free surfactant concentration are controlled via two single control loops. In this work, a new control strategy for controlling monomer conversion has been proposed. It has been shown that monomer... 

    Theoretical and experimental investigations of the inverse emulsion polymerization of acrylamide

    , Article Journal of Applied Polymer Science ; Volume 132, Issue 22 , February , 2015 ; 00218995 (ISSN) Abdi, A ; Shahrokhi, M ; Ahmad Ramazani, S. A ; Vafa, E ; Sharif University of Technology
    John Wiley and Sons Inc  2015
    In this study, the inverse emulsion polymerization modeling of polyacrylamide with population balance equations (PBEs) was performed. The PBEs were derived on the basis of the zero-one kinetic model. The effects of the surfactant steric barrier and surfactant reaction with radicals, including monomeric radicals, on the radical entry rate into the particle were taken into account. In the modified model, the coagulation phenomenon was included through consideration of the effects of forces not included in the Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory; these include hydration and steric forces in addition to DLVO forces. The effects of the surfactant and initiator concentrations on... 

    Inverse emulsion polymerization of triple monomers of acrylamide, maleic anhydride, and styrene to achieve highly hydrophilic–hydrophobic modified polyacrylamide

    , Article Journal of Applied Polymer Science ; Volume 136, Issue 29 , 2019 ; 00218995 (ISSN) Lalehgani, Z ; Ramazani S. A., A ; Tamsilian, Y ; Shirazi, M ; Sharif University of Technology
    John Wiley and Sons Inc  2019
    The purpose of this study was the production of copolymers and terpolymers with highly hydrophilic–hydrophobic properties, using inexpensive and available monomers as potential enhancing oil recovery (EOR) and water production control agents for high-temperature and high-salinity (HTHS) oil reservoirs. For this purpose, several copolymers and terpolymers with different molar percentage of acrylamide/styrene, acrylamide/maleic anhydride, and acrylamide/styrene/maleic anhydride were synthesized by the inverse emulsion polymerization technique. The presence of hydrophobic styrene and hydrophilic maleic anhydride monomers in the copolymer and terpolymer structure, provided some unique properties... 

    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) Moghbeli, M. R ; Mohammadi, N ; Bagheri, R ; Sharif University of Technology
    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... 

    Study of Physical Properties of Poly(1,3 Butadiene-co-Acrylic acid-co-Acrylonitrile) Terpolymer

    , M.Sc. Thesis Sharif University of Technology Tati, Ali (Author) ; Musavi, Abbas (Supervisor)
    Butadiene is one of the most widely used materials in the Iran polymer industry. In order to use this material in the first step, the inhibitor must be separated. Consequently, at the start of the project, the separation of Tert butylcatechol inhibitors from butadiene was studied by the adsorption process on active alumina. The results of the condensed butadiene gas chromatography–mass spectrometry test indicate that, by using the active alumina as an adsorbent, the tert butylcatechol will be removed completely. In the next step, 1,3 butadiene, acrylonitrile, acrylic acid acid terpolymer, which one of its applications is manufacturing of artificial teeth, was synthesized by emulsion... 

    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) Abedini, H ; Shahrokhi, M ; Sharif University of Technology
    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... 

    High molecular weight polyacrylamide nanoparticles prepared by inverse emulsion polymerization: reaction conditions-properties relationships

    , Article Colloid and Polymer Science ; Volume 294, Issue 3 , 2016 , Pages 513-525 ; 0303402X (ISSN) Tamsilian, Y ; Ramazani S. A ; Shaban, M ; Ayatollahi, S ; Tomovska, R ; Sharif University of Technology
    Springer Verlag  2016
    High molecular weight polyacrylamide (PAM) nanoparticle dispersions are products with wide application possibilities, the most important of which is in petroleum industry such as drilling fluid and flooding agent in enhanced oil recovery. For that aim, it is necessary to achieve complete control of the final dispersion and polymer properties during the synthesis step. In this work, PAMs were synthesized by inverse emulsion polymerization of aqueous acrylamide solution in cyclohexane in the presence of emulsifier mixture of Span 20 and Span 80. We present a comprehensive study of the effects of variation of all important reaction conditions (agitation rate, reaction time and temperature,... 

    Study of the Poly (vinyl acetate)/SiO2 Nanocomposites Produced by in Situ Polymerization

    , M.Sc. Thesis Sharif University of Technology Azamian Jazi, Mehrdad (Author) ; Ramazani Saadat Abadi, Ahmad (Supervisor)
    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... 

    Evaluating the Effects of Operating Conditions on Particle Size and Molecular Weight Distributions in Emulsion Polymerization of Styrene

    , M.Sc. Thesis Sharif University of Technology Vafa, Ehsan (Author) ; Shahrokhi, Mohammad (Supervisor)
    In this work, a comprehensive dynamic model has been used for styrene emulsion polymerization in a semi-batch reactor to predict the evolution of product particle size and molecular weight distributions under non-isothermal condition. Method of moments has been applied for solving the population balance equations and the results are compared with the results obtained from finite-volume method as a precise technique. A sensitivity analysis respect to perturbation in initial values of various reagents, species and the reactor temperature has been performed to identify suitable manipulated variables for closed-loop control of the reactor. The detailed model is used to generate optimal feed... 

    Surface modification of cotton fabric with dual-responsive PNIPAAm/chitosan nano hydrogel

    , Article Polymers for Advanced Technologies ; Volume 24, Issue 9 , MAY , 2013 , Pages 797-806 ; 10427147 (ISSN) Bashari, A ; Hemmatinejad, N ; Pourjavadi, A ; Sharif University of Technology
    The present study deals with preparing stimuli-responsive poly N-isopropyl acryl amide/chitosan (PNCS) nano hydrogel and looks into their effects as a surface modifying system of cotton fabric. The semi-batch surfactant-free emulsion polymerization method was proposed to reduce the size of particle and synthesis of PNCS nano particles. Fourier transform infrared, nuclear magnetic resonance, differential scanning calorimetry, scanning electron microscopy and dynamic light scattering methods confirmed the nano size of synthesized PNCS particles and sensitivity of these nano particles to the different temperature and pH, respectively. The water retention capacity (WRC) and carboxyl content of... 

    Inferential closed-loop control of particle size and molecular weight distribution in emulsion polymerization of styrene

    , Article Polymer Engineering and Science ; Volume 50, Issue 12 , 2010 , Pages 2306-2320 ; 00323888 (ISSN) Vafa, E ; Shahrokhi, M ; Abedini, H ; Sharif University of Technology
    In this work, simultaneous inferential control of particle size distribution (PSD) and molecular weight distribution (MWD) in a semi-batch emulsion polymerization reactor of styrene has been addressed. Using a comprehensive dynamic model for PSD and MWD predictions and performing a sensitivity analysis, it has been revealed that free surfactant and chain transfer agent (CTA) concentrations in the reactor are the most suitable candidates for inferential control of PSD and MWD, respectively. To control concentrations of these species in the reactor, their inlet feed flow rates are used as manipulated variables. It is assumed that the concentration of CTA is measured infrequently and therefore... 

    Simulation and experimental evaluation of initiator and surfactant concentrations and temperature effects on styrene conversion and polymer particle size distribution in batch emulsion polymerization

    , Article Iranian Polymer Journal (English Edition) ; Volume 19, Issue 8 , Aug , 2010 , Pages 599-614 ; 10261265 (ISSN) Abedini, H ; Shahrokhi, M ; Sharif University of Technology
    Effects of initiator and surfactant concentrations and temperature on styrene conversion and polymer particle size distribution (PSD) in a batch emulsion polymerization are investigated through simulation and experimental studies. The detailed model based on population balance (zero-one model), accounting for nucleation, growth and coagulation phenomena has been used for prediction of particle size distribution. In checking the effect of initiator concentration on final PSD, it was noticed that when critical micelle concentration (CMC) is kept constant, the model cannot predict PSD very well. Thus, a correlation for calculating critical micelle concentration has been proposed and... 

    Nanostructured particles for controlled polymer release in enhanced oil recovery

    , Article Energy Technology ; Volume 4, Issue 9 , 2016 , Pages 1035-1046 ; 21944288 (ISSN) Tamsilian, Y ; Ramazani S., A ; Shaban, M ; Ayatollahi, S ; de la Cal, J. C ; Sheng, J. J ; Tomovska, R ; Sharif University of Technology
    Wiley-VCH Verlag  2016
    With the decline in oil discoveries over recent decades, it is believed that enhanced oil recovery (EOR) technologies will play a key role to meet energy demand in the coming years. Polymer flooding is used commonly worldwide as an EOR process. In this work, we propose the synthesis of protected polyacrylamide (PAM) nanoparticles (PPNs) with a hydrophobic polystyrene (PSt) shell by one-pot two-step inverse emulsion polymerization, in which the PSt shell was created by surface polymerization. The shell protects the active PAM chains from premature degradation caused by the harsh environment in the reservoirs, controls the release of the chains as rheological modifiers, and additionally, it... 

    Paclitaxel molecularly imprinted polymer-PEG-folate nanoparticles for targeting anticancer delivery: Characterization and cellular cytotoxicity

    , Article Materials Science and Engineering C ; Volume 62 , 2016 , Pages 626-633 ; 09284931 (ISSN) Esfandyari Manesh, M ; Darvishi, B ; Azizi Ishkuh, F ; Shahmoradi, E ; Mohammadi, A ; Javanbakht, M ; Dinarvand, R ; Atyabi, F ; Sharif University of Technology
    Elsevier Ltd  2016
    The aim of this work was to synthesize molecularly imprinted polymer-poly ethylene glycol-folic acid (MIP-PEG-FA) nanoparticles for use as a controlled release carrier for targeting delivery of paclitaxel (PTX) to cancer cells. MIP nanoparticles were synthesized by a mini-emulsion polymerization technique and then PEG-FA was conjugated to the surface of nanoparticles. Nanoparticles showed high drug loading and encapsulation efficiency, 15.6 ± 0.8 and 100%, respectively. The imprinting efficiency of MIPs was evaluated by binding experiments in human serum. Good selective binding and recognition were found in MIP nanoparticles. In vitro drug release studies showed that MIP-PEG-FA have a... 

    Applications of highly salt and highly temperature resistance terpolymer of acrylamide/styrene/maleic anhydride monomers as a rheological modifier: Rheological and corrosion protection properties studies

    , Article Journal of Molecular Liquids ; Volume 294 , 2019 ; 01677322 (ISSN) Ghaderi, S ; Ramezani Saadat Abadi, A ; Haddadi, A ; Sharif University of Technology
    Elsevier B.V  2019
    Due to the weak performance of commercially affordable natural and synthetic polymeric thickeners in high temperatures and salinity, they fail to use in many applications especially in saline conditions with high temperatures. In this work, a new salt and temperature resistance acrylamide/styrene/maleic anhydride terpolymer (PASM-t) with self-associative properties was synthesized via a one-step inverse emulsion polymerization and its applicability as a rheological modifier and thickener was investigated. The characteristics of synthesized PASM-t (s-PASM-t) and its aqueous solutions were investigated using FT-IR, FE-SEM, GPC and rheometric mechanical spectrometry (RMS) analyses. The... 

    In situ emulsion polymerization and characterization of PVAc nanocomposites including colloidal silica nanoparticles for wood specimens bonding

    , Article Journal of Applied Polymer Science ; Volume 137, Issue 15 , 2020 Azamian Jazi, M ; Ramezani Saadat Abadi, A ; Haddadi, S. A ; Ghaderi, S ; Azamian, F ; Sharif University of Technology
    John Wiley and Sons Inc  2020
    Polyvinyl acetate (PVAc) nanocomposites for wood adhesives containing different amounts of colloidal silica nanoparticles (CSNs) were synthesized via in situ one-step emulsion polymerization. The adhesion strength of wood specimens bonded by PVAc nanocomposites was investigated by the tensile test. Thermal properties of PVAc nanocomposites were also characterized by differential scanning calorimetry and thermogravimetric analysis. Rheological and morphological properties of the PVAc nanocomposites were investigated using rheometric mechanical spectrometry and field emission scanning electron microscopy (FESEM), respectively. The obtaining results showed that the shear strength of PVAc... 

    Fabrication and Properties Investigation of Acrylamide Terpolymer Containing Silica Nanoparticles to Use in Drilling Fluids

    , M.Sc. Thesis Sharif University of Technology Ghaderi, Saeed (Author) ; Ramazani, Ahmad (Supervisor) ; Haddadi, Arash (Co-Supervisor)
    Most used polymers, such as hydrolyzed polyacrylamide, are not able to withstand high levels of salinity and high temperature of the reservoirs. To overcome these problems, in this project, new types of microstructures based on modified acrylamide with hydrophilic groups (malic anhydride monomer) and hydrophobic groups (styrene monomer) using inversible mini-emulsion were synthesized. The structure of the synthesized terpolymer was investigated using methods of FT-IR and 1H NMR. The micro-structure and the particle-size of the terpolymer particles were studied with the scanning electron microscopy (FE-SEM) and differential light scattering (DLS) method and the results showed that the average... 

    Modeling, Simulation and Production of Nanoparticles PAM by Inverse Emulsion Polymerization Method

    , Ph.D. Dissertation Sharif University of Technology Abdi, Ardeshir (Author) ; Ramazani Saadat abadi, Ahmad (Supervisor) ; Shahrokhi, Mohammad (Supervisor) ; Abedini, Hossein (Co-Advisor)
    In this project, inverse emulsion polymerization (IEP) modeling of poly acrylamid (PAM) using population balance equations (PBEs) has been performed. For this porpuse zero-one and pseudo- bulk models and hybrid model including the zero-one and pseudo- bulk are applied based on the process conditions. The effects of surfactant steric barrier and surfactant reaction with radicals including monomeric radicals on the radical entry rate into the particle have been taken into account for these models. In the modeling, coagulation phenomenon was included by considering the effects of non-DLVO forces such as hydration and steric forces in addition to the DLVO forces. Simulation results for zero-... 

    Preparation of Polyacrylamide Nanoparticle with Nanoscale Coating to Control Solubility of Polymer during Polymer Flooding Process

    , M.Sc. Thesis Sharif University of Technology Tamsilian,Yousef (Author) ; Ramezani Saadat, Ahmad (Supervisor)
    Hydrophilic polymers are widely used in enhanced oil recovery (EOR) processes to increase water viscosity during polymer flooding. However, these polymers increase the viscosity of injected water in undesirable strands, before reaching considerable positions that make some problems in polymer flooding process such as thermal, mechanical, bacterial degradation, surface absorption and undesirable plugging. In this study, a novel core-shell structure of polyacrylamide as an active polymer and nanoscale coating polystyrene as a shell polymer was designed and prepared to intelligently control mobility ratio in oil reservoirs and overcome weakness and limitations of classical polymer flooding....