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Lithium perchlorate promoted highly regioselective ring opening of epoxides under solvent-free conditions
, Article Catalysis Communications ; Volume 8, Issue 12 , December , 2007 , Pages 2198-2203 ; 15667367 (ISSN) ; Mirmashhori, B ; Saidi, M. R ; Sharif University of Technology
2007
Abstract
A simple and efficient synthesis of diol diesters, protected chlorohydrins, chlorohydrins and β-hydroxy azides with acetyl or benzoyl, TMSN3 and TMSCl groups has been achieved by ring opening of epoxides with acetic anhydride, acetyl chloride or benzoyl chloride and TMSN3 using catalytic amount of lithium perchlorate under solvent-free conditions. All reactions proceeded in short times and afforded the corresponding products in good to excellent yields under mild reaction conditions. LiClO4 shows enhanced reactivity for the ring opening of epoxides under solvent-free conditions, therefore, reducing the reaction times dramatically and improved the yields and amount of catalyst. © 2007...
Facile preparation of a highly sensitive non-enzymatic glucose sensor based on the composite of Cu(OH)2 nanotubes arrays and conductive polypyrrole
, Article Microchemical Journal ; Volume 169 , 2021 ; 0026265X (ISSN) ; Shahrokhian, S ; Hafezi Kahnamouei, M ; Sharif University of Technology
Elsevier Inc
2021
Abstract
A novel amperometric non-enzymatic glucose sensor is designed by the facile preparation method. It is made by electrodeposition of Cu clusters and converting them to Cu(OH)2 nanotubes (Cu(OH)2NTs) arrays along with thin-film electro-polymerized of spindle-shaped polypyrrole (PPy@Cu(OH)2NTs), which have been doped by using sodium Benzene-1,3-disulfonate as an anion dopant. Various electrochemical methods investigate the electrochemical performance of the modified electrode toward glucose detection. Under the optimized conditions, a significant electrochemical response improvement is observed toward the electro-oxidation of glucose on the PPy@Cu(OH)2NTs electrode's surface relative to the...
Microwave-assisted synthesis of bithiazole derivatives under solvent-free conditions
, Article Russian Journal of Organic Chemistry ; Volume 41, Issue 4 , 2005 , Pages 623-624 ; 10704280 (ISSN) ; Asadollahi, H ; Mostaghim, R ; Sharif University of Technology
2005
Modified CMC. 3. Carboxymethylcellulose-g-poly(acrylamidrazone) as a new metal adsorbent
, Article Journal of Polymer Materials ; Volume 21, Issue 3 , 2004 , Pages 315-320 ; 09738622 (ISSN) ; Pourjavadi, A ; Salehi Rad, M ; Sharif University of Technology
2004
Abstract
A new poly(acrylamidrazone) chelating resin was prepared from carboxymethylcellulose (CMC) via a two-step process. First, acrylonitrile was graft polymerized onto the substrate. The CMC-polyacrylonitrile graft copolymer was then treated with hydrazine to yield a triply modified cellulose containing amidrazone functional groups. The resin was characterized using infrared spectroscopy. The sorption capacity of the resin towards bivalent metal ions was evaluated versus variation of pH and hydrochloric acid concentration. The adsorption capacities at pH 6 were found to be in order Cu2+> Zn2+>Cd2+>Co2+>Ni2+. The metal ion sorption capacities were varied in the range of 2.0-20.0 mmol metal per...
Molecular weight control of a batch suspension polymerization reactor
, Article Iranian Polymer Journal (English Edition) ; Volume 11, Issue 6 , 2002 , Pages 403-411 ; 10261265 (ISSN) ; Fanaei, M. A ; Sharif University of Technology
2002
Abstract
This paper concerns molecular weight control of a batch polymerization reactor where suspension polymerization of methyl methacrylate(MMA) takes place. For this purpose, a cascade control structure with two control loops has been selected. The slave loop is used for temperature control using on-line temperature measurements, and the master loop controls the average molecular weights based on its estimated values. Two different control algorithms namely proportional-integral(PI) controller and globally linearizing controller (GLC) have been used for temperature control. An estimator, which has the structure of an extended Kalman filter (EKF), is used for estimating monomer conversion and...
State estimation in a batch suspension polymerization reactor
, Article Iranian Polymer Journal (English Edition) ; Volume 10, Issue 3 , 2001 , Pages 173-187 ; 10261265 (ISSN) ; Fanaei, M. A ; Sharif University of Technology
2001
Abstract
This paper concerns non-linear state estimation in a batch polymerization reactor where suspension polymerization of methyl methacrylate takes place. A kinetic model proposed in the literature is selected and its validity has been verified through an experimental set-up. Based on this model monomer conversion and average molecular weights of the polymer are estimated using only one output measurement (reactor temperature). The performance of the estimator, which has the structure of an extended Kalman filter, is examined through simulation and experimental studies in the presence of different levels of parameter uncertainties. The effects of adding 'fictitious noise' and parameter state' to...
Preparation of poly (acrylic acid) microgels by alcohol type cross-linkers and a comparison with other cross-linking methods
, Article Polymer Bulletin ; Volume 79, Issue 9 , 2022 , Pages 7775-7794 ; 01700839 (ISSN) ; Bouhendi, H ; Keshavarzi, N ; Mahmoudi, M ; Pourjavadi, A ; Ghiass, M ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
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,...
Synthesis and characterization of magnetic hybrid nanomaterials via RAFT polymerization: A pH sensitive drug delivery system
, Article Colloids and Surfaces B: Biointerfaces ; Volume 174 , 2019 , Pages 153-160 ; 09277765 (ISSN) ; Kohestanian, M ; Shirzad, M ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Herein, a facile and versatile method for the synthesis of a novel magnetic nanocarrier via surface- initiated reversible addition-fragmentation chain transfer (RAFT) polymerization is introduced. At first, RAFT agent was successfully attached to the surface of Fe 3 O 4 nanoparticles and, then, poly (glycidyl methacrylate) (PGMA) chains were grown and anchored onto the surface of Fe 3 O 4 nanoparticles. At the end, hydrazine (Hy) groups were introduced to the PGMA chains via reaction between epoxy rings and hydrazine molecules. Doxorubicin (DOX) was covalently conjugated to the prepared nanocarrier (Fe 3 O 4 @PGMA@Hy) through a hydrazone linkage. The in vitro drug release of Fe 3 O 4...
Synthesis of Molecularly Imprinted Nano-porous Polymer for the Enrichment of Taxol as Anti-Cancer Agent
, M.Sc. Thesis Sharif University of Technology ; Abdekhodaie, Mohammad Jafar (Supervisor) ; Nematollahzadeh, Ali (Co-Advisor) ; Musavi, Abbas (Co-Advisor)
Abstract
In the present research, first, a series of molecular dynamics (MD) simulations of pre-polymerization mixtures for taxol (template) imprinted polymers was performed to select an appropriate monomer and its intermolecular bonds with the template. Finally, after synthesis, performance and morphological evaluation of taxol imprinted polymer were presented. In the molecular modeling step, a virtual library of functional monomers was created containing eleven frequently used monomers. The MD simulations were first conducted to select the optimum monomer from the virtual library using acetonitrile as porogen. Methacrylic acid among the studied functional monomers was found to possess stronger...
Design and Fabrication of Polymeric Drug Delivery System and Investigation of its Release Behavior
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Manoochehr (Supervisor) ; Alizadeh, Ali (Supervisor)
Abstract
In the present study we examined the fabrication of electrospun polymer drug delivery system for the production of polymeric film containing Rizatriptan drug. Fabricated films were underwent X-ray diffraction and DSC tests to ensure that the drug is not in crystalline and amorphous form. And the results revealed the fact that the drug is fully dispersed in the polymer. pH changes in the aqueous phase is too low so that it enable the polymeric film to be suitable for use in oral administration. In-vitro assay for different combination of sublingual polymeric suggested that Rizatriptan film with 3% weight by volume and 30% by weight by volume of electrospun polymer PVP is the best combination...
An Analytical Solution for the Polymeric Liner Collapse in Hyperbaric type IV Hydrogen Storage Vessels
, M.Sc. Thesis Sharif University of Technology ; Naghdabadi, Reza (Supervisor)
Abstract
Type IV high pressure vessels are composite vessels with a polymeric liner, which are the best choice for storing hydrogen in hydrogen vehicles. The defect of these vessels is the penetration of light hydrogen molecules in the polymeric liner and the composite part. When depressurization the vessel, these molecules cannot release from the polymeric liner and the composite part according to the emptying rate of the vessel. Thus, concentration of the hydrogen molecules in the polymeric liner becomes more than inside the vessel which leads to a pressure difference between the two sides of the polymeric liner that causes the liner collapse. In this research, the partial differential equation for...
Property investigation of polypropylene/multiwall carbon nanotube nanocomposites prepared via in situ polymerization
, Article Polymer International ; Vol. 63, issue. 4 , April , 2014 , pp. 689-694 ; ISSN: 09598103 ; Ramazani, S. A ; Azinfar, B ; Sharif University of Technology
Abstract
In this study, polypropylene/carbon nanotube nanocomposites were prepared via in situ polymerization using a bi-supported Ziegler-Natta catalytic system. In this system, magnesium ethoxide and multiwall carbon nanotubes (MWCNTs) are jointly used as catalyst supports. SEM images reveal the distribution and quite good dispersion of MWCNTs throughout the polypropylene (PP) matrix. The thermal properties of the samples were examined using DSC and TGA tests. The results show that the crystallization temperature of the nanocomposites significantly increases while the melting point is not markedly affected. In addition, the thermal stability is improved. The melt rheological properties of PP/MWCNT...
Novel cationic-modified salep as an efficient flocculating agent for settling of cement slurries
, Article Carbohydrate Polymers ; Volume 93, Issue 2 , April , 2013 , Pages 506-511 ; 01448617 (ISSN) ; Fakoorpoor, S. M ; Hosseini, S. H ; Sharif University of Technology
2013
Abstract
A new cationic flocculant was synthesized by graft copolymerization of acrylamide (AM) and 3-(methacryloylamino)propyl]trimethylammonium chloride (MAPTAC) onto salep using free radical polymerization initiated by ammonium persulfate (APS) to produce cationic salep [S-g-P(AM-co-MAPTAC)]. Reaction parameters (monomers/salep ratio, concentration of reactants, MAPTAC/AM ratio, and APS) were optimized using a full factorial experimental design to obtain the highest settling rate for cement suspensions. The best performing product was characterized by gel permeation chromatography (GPC), FTIR, 1H NMR spectroscopy, and thermogravimetric analysis (TGA). The resulted cationic flocculant may be...
Synthesis and characterization of semi-conductive nanocomposite based on hydrolyzed collagen and in vitro electrically controlled drug release study
, Article Polymer (United Kingdom) ; Volume 76 , October , 2015 , Pages 287-294 ; 00323861 (ISSN) ; Doroudian, M ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
In this study, a semi-conductive nanocomposite for electrically controlled drug delivery is introduced. Hydrolyzed collagen known as a naturally abundant polypeptide was modified with polycaprolactone. This modification changed the mechanical properties of the hydrolyzed-collagen. A hydrogel compound was synthesized through radical co-polymerization of acrylic acid on the backbone of this biocompatible polymer in the presence of a crosslinker. The reaction parameters affecting the water absorbency of the hydrogel were optimized using Taguchi method. In situ polymerization of aniline, incorporated conductive nanofiber pathways throughout the hydrogel matrix. 1H NMR, TGA, AFM, SEM, FTIR,...
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) ; Shahrokhi, M ; Abedini, H ; Vafa, E ; Guay, M ; Gopaluni, B ; Huang, B ; Findeisen, R ; Sharif University of Technology
IFAC Secretariat
2015
Abstract
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) ; Shahrokhi, M ; Ahmad Ramazani, S. A ; Vafa, E ; Sharif University of Technology
John Wiley and Sons Inc
2015
Abstract
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...
Improvement in mechanical performance of anionic hydrogels using full-interpenetrating polymer network reinforced with graphene oxide nanosheets
, Article Advances in Polymer Technology ; Volume 35, Issue 4 , 2016 , Pages 386-395 ; 07306679 (ISSN) ; Bagheri, R ; Kabiri, K ; Ossipov, D. A ; Jokar, E ; Asadian, E ; Sharif University of Technology
John Wiley and Sons Inc
Abstract
Weak mechanical possession is one of the limiting factors in application of hydrogels. To modify this inherent disadvantage, different approaches have been studied including synthesizing interpenetrating polymer network (IPN) and nanocomposite hydrogels. So, this study has focused on preparation of a novel full-IPN structure based on anionic monomers of 2-acrylamido-2-methylpropane sulfonic acid/acrylic acid–sodium acrylate via facile solution polymerization technique in an aqueous media with incorporation of graphene oxide (GO) nanosheets. Mechanical performance of materials in the “as-prepared condition” and “swollen state” was characterized via tensile, compression, and rheology tests,...
PVDF/PAN blend membrane: preparation, characterization and fouling analysis
, Article Journal of Polymers and the Environment ; 2016 , Pages 1-11 ; 15662543 (ISSN) ; Azimi Yancheshme, A ; Rekaabdar, F ; Hemmati, M ; Tavakolmoghadam, M ; Safekordi, A ; Sharif University of Technology
Springer New York LLC
2016
Abstract
Ultrafiltration membranes were prepared from blend of the poly(vinylidene fluoride) (PVDF) with polyacrylonitrile (PAN) via phase inversion method induced by immersion precipitation. N,N-dimethylacetamide (DMAc) and water were used as solvent and coagulant (non-solvent), respectively. The effect of blending ratio on the morphology and antifouling behavior of the prepared membranes was investigated. The performance of the membranes was evaluated by using cross flow filtration of pure water and buffered bovine serum albumin (BSA) solution as feed. Contact angle measurements indicated that the hydrophilicities of the PVDF/PAN membranes increased by increasing PAN concentration in the casting...
Synthesis of Conductive Magnetite Nanocomposite based on Polyaniline/Poly(maleic acid-co-acrylic acid) with Core-Shell Structure
, Article Advances in Polymer Technology ; 2016 ; 07306679 (ISSN) ; Najafi Moghadam, P ; Mahmoodi Hashemi, M ; Sharif University of Technology
John Wiley and Sons Inc
2016
Abstract
In this study, a new type of magnetite nanocomposite with a core-shell structure was synthesized using Fe3O4 nanoparticles as a core and polyaniline (PANI) as a shell. For this propose, the surface of Fe3O4 was chemically modified with hexamethylenediisocyanate (HMDI) to improve its compatibility and interphase interaction with the polymeric matrix. Thereafter, the PANI was reacted with modified Fe3O4 to anchor them to PANI by covalent bands which acted as a shell. In the second step, the poly (maleic acid-co-acrylic acid) (P(MAc-co-AA)) as polymeric dopant for the PANI was synthesized. Finally, the PANI anchored to Fe3O4 was immersed in an aqueous solution of poly (maleic...
PVDF/PAN blend membrane: preparation, characterization and fouling analysis
, Article Journal of Polymers and the Environment ; Volume 25, Issue 4 , 2017 , Pages 1348-1358 ; 15662543 (ISSN) ; Yancheshme, A. A ; Rekaabdar, F ; Hemmati, M ; Tavakolmoghadam, M ; Safekordi, A ; Sharif University of Technology
Abstract
Ultrafiltration membranes were prepared from blend of the poly(vinylidene fluoride) (PVDF) with polyacrylonitrile (PAN) via phase inversion method induced by immersion precipitation. N,N-dimethylacetamide (DMAc) and water were used as solvent and coagulant (non-solvent), respectively. The effect of blending ratio on the morphology and antifouling behavior of the prepared membranes was investigated. The performance of the membranes was evaluated by using cross flow filtration of pure water and buffered bovine serum albumin (BSA) solution as feed. Contact angle measurements indicated that the hydrophilicities of the PVDF/PAN membranes increased by increasing PAN concentration in the casting...