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    Modified carrageenan. 5. Preparation, swelling behavior, salt- and pH-sensitivity of partially hydrolyzed crosslinked carrageenan-graft-polymethacrylamide superabsorbent hydrogel [electronic resource]

    , Article Polymers for Advanced Technologies ; Volume 15, Issue 11, pages 645–653, November 2004 Pourjavadi, A. (Ali) ; Sadeghi, M ; Hosseinzadeh, H
    Abstract
    The polysaccharide, kappa-carrageenan (κC) was chemically modified to achieve a novel superabsorbent hydrogel via graft copolymerization of methacrylamide (MAM) onto the substrate followed by alkaline hydrolysis. Ammonium persulfate (APS) and N,N′-methylene bisacrylamide (MBA) were used as a free-radical initiator and a crosslinker, respectively. The saponification reaction was carried out using sodium hydroxide aqueous solution. Either κC-g-PMAM or hydrolyzed κC-g-PMAM (PMAM: polymethacrylamide) was characterized by FT-IR spectroscopy. The effect of grafting variables (i.e. concentration of MBA, MAM, and APS) and alkaline hydrolysis conditions (i.e. NaOH concentration, hydrolysis time and... 

    Modified carrageenan. 5. Preparation, swelling behavior, salt- and pH-sensitivity of partially hydrolyzed crosslinked carrageenan-graft-polymethacrylamide superabsorbent hydrogel

    , Article Polymers for Advanced Technologies ; Volume 15, Issue 11 , 2004 , Pages 645-653 ; 10427147 (ISSN) Pourjavadi, A ; Sadeghi, M ; Hosseinzadeh, H ; Sharif University of Technology
    2004
    Abstract
    The polysaccharide, kappa-carrageenan (kC) was chemically modified to achieve a novel superabsorbent hydrogel via graft copolymerization of methacrylamide (MAM) onto the substrate followed by alkaline hydrolysis. Ammonium persulfate (APS) and N,N'-methylene bisacrylamide (MBA) were used as a free-radical initiator and a crosslinker, respectively. The saponification reaction was carried out using sodium hydroxide aqueous solution. Either kC-g-PMAM or hydrolyzed kC-g-PMAM (PMAM: polymethacrylamide) was characterized by FT-IR spectroscopy. The effect of grafting variables (i.e.concentration of MBA, MAM, and APS) and alkaline hydrolysis conditions (i.e. NaOH concentration, hydrolysis time and... 

    Modified carrageenan. 1. H-carragPAM, a novel biopolymer-based superabsorbent hydrogel [electronic resource]

    , Article Journal of Bioactive and Compatible Polymers ; September 2005 Vol. 20 no. 5 475-490 Hosseinzadeh, H. (Hossein) ; Pourjavadi, A ; Mahdavinia, G. R ; Zohuriaan-Mehr, , M. J
    Abstract
    A novel kappa-carrageenan (C)-based superabsorbing hydrogel was synthesized through graft copolymerization of acrylamide (AAm) onto a C substrate in the presence of a crosslinking agent. The crosslinked C-poly(AAm) polymer graft was partially hydrolyzed in alkaline medium to yield a superabsorbent resin, H-carragPAM. The resin structure was confirmed using FTIR spectroscopy. The variables of graft copolymerization (monomer, initiator, polysaccharide and crosslinker concentration, reaction temperature and time as well as stirrer speed) that affected on the ultimate water-swelling capacity were optimized. The time-temperature variation of the copolymerization was investigated in terms of the... 

    Modified carrageenan. 4. Synthesis and swelling behavior of crosslinked kappa C-g-AMPS superabsorbent hydrogel with antisalt and pH-responsiveness properties [electronic resource]

    , Article Journal of Applied Polymer Science ; Vol.98, No.1, 255-263, 2005 Pourjavadi, A. (Ali) ; Hosseinzadeh, H ; Mazidi, R
    Abstract
    To synthesize a novel biopolymer-based superabsorbent hydrogel, 2-acrylamido-2-methylpropanesulfonic acid (AMPS) was grafted onto kappa-carrageenan (KC) backbones. The graft copolymerization reaction was carried out in a homogeneous medium and in the presence of ammonium persulfate (APS) as an initiator, N,N,N',N'-tetramethyl ethylenediamine (TMEDA) as an accelerator, and N,N'-methylene bisacrylamide (MBA) as a crosslinker. A proposed mechanism for KC-g-AMPS formation was suggested and the hydrogel structure was confirmed using FTIR spectroscopy. The affecting variables on swelling capacity, i.e., the initiator, the crosslinker, and the monomer concentration, as well as reaction temperature,... 

    Modified carrageenan. 6. Crosslinked graft copolymer of methacrylic acid and kappa-carrageenan as a novel superabsorbent hydrogel with low salt- and high pH-sensitivity

    , Article Macromolecular Research ; Volume 13, Issue 6 , 2005 , Pages 483-490 ; 15985032 (ISSN) Pourjavadi, A ; Harzandi, A. M ; Hosseinzadeh, H ; Sharif University of Technology
    Polymer Society of Korea  2005
    Abstract
    A novel, polysaccharide-based, superabsorbent hydrogel was synthesized through crosslinking graft copolymerization of methacrylic acid (MAA) onto kappa-carrageenan (κC), using ammonium persulfate (APS) as a free radical initiator in the presence of methylenebisacrylamide (MBA) as a crosslinker. A proposed mechanism for κC-g-polymethacrylic acid (κC-g-PMAA) formation was suggested and the hydrogel structure was confirmed using FTIR spectroscopy. The effect of grafting variables, including MBA, MAA, and APS concentration, was systematically optimized to achieve a hydrogel with the maximum possible swelling capacity. The swelling kinetics in distilled water and various salt solutions were... 

    Porous Carrageenan-g-polyacrylamide/bentonite superabsorbent composites: swelling and dye adsorption behavior

    , Article Journal of Polymer Research ; Volume 23, Issue 3 , 2016 , Pages 1-10 ; 10229760 (ISSN) Pourjavadi, A ; Bassampour, Z ; Ghasemzadeh, H ; Nazari, M ; Zolghadr, L ; Hosseini, S. H ; Sharif University of Technology
    Springer Netherlands  2016
    Abstract
    A novel superabsorbent composite based on kappa-Carrageenan (κC) was prepared by graft copolymerization of acrylamide (AAm) onto κC in the presence of bentonite powder using methylenebisacrylamide (MBA) as a crosslinking agent, ammonium persulfate (APS) as an initiator, and sodium carbonate as a pore-forming agent. The swelling behavior in distilled water and in solutions with different pH values was investigated. The results indicated that with increasing carrageenan/bentonite weight ratio, the swelling capacity is increased but the gel content is decreased. The swelling rate of the hydrogels was improved by introducing sodium carbonate as pore-forming agent. The prepared superadsorbent... 

    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) Hosseinzadeh, H ; 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 carrageenan 3. Synthesis of a novel polysaccharide-based superabsorbent hydrogel via graft copolymerization of acrylic acid onto kappa-carrageenan in air

    , Article European Polymer Journal ; Volume 40, Issue 7 , 2004 , Pages 1363-1370 ; 00143057 (ISSN) Pourjavadi, A ; Harzandi, A. M ; Hosseinzadeh, H ; Sharif University of Technology
    2004
    Abstract
    A novel biopolymer-based superabsorbent hydrogel was synthesized through chemically crosslinking graft copolymerization of acrylic acid (AA) onto kappa-carrageenan (κC), in the presence of a crosslinking agent and a free radical initiator. A proposed mechanism for κC-g-polyacrylic acid was suggested and the affecting variables onto graft polymerization (i.e. the crosslinker, the monomer and the initiator concentration, the neutralization percent and reaction temperature) were systematically optimized to achieve a hydrogel with swelling capacity as high as possible. Maximum water absorbency of the optimized final product was found to be 789 g/g. The swelling capacity of the synthesized... 

    Grafting of acrylamide onto kappa-carrageenan via γ-irradiation: Optimization and swelling behavior

    , Article Radiation Physics and Chemistry ; Volume 77, Issue 2 , 2008 , Pages 131-137 ; 0969806X (ISSN) Rezanejade Bardajee, G ; Pourjavadi, A ; Sheikh, N ; Sadegh Amini Fazl, M ; Sharif University of Technology
    2008
    Abstract
    The Taguchi method, a robust experimental design for optimization, was used for the synthesis of a superabsorbent hydrogel network using γ-rays as an initiator, energy source and crosslinker at the same time. Nine different samples of superabsorbent hydrogels were prepared in various conditions from kappa-carrageenan (κC) and acrylamide by γ-irradiation at room temperature. Considering the results of nine trials and according to analysis of variance (ANOVA), a new experimental condition with the concentrations of κC and acrylamide 1.5 g and 0.028 mol (2 g in total volume of 50 mL H2O), respectively, as well as γ-ray at the optimum total dose (7 kGy) was proposed. After preparing the desired... 

    Magnetic/pH-sensitive κ-carrageenan/sodium alginate hydrogel nanocomposite beads: Preparation, swelling behavior, and drug delivery

    , Article Journal of Biomaterials Science, Polymer Edition ; Vol. 25, issue. 17 , 2014 , p. 1891-1906 Mahdavinia, G. R ; Rahmani, Z ; Karami, S ; Pourjavadi, A ; Sharif University of Technology
    Abstract
    This work describes the preparation of magnetic and pH-sensitive beads based on κ-carrageenan and sodium alginate for use as drug-targeting carriers. Physical cross-linking using K+/Ca2+ ions was applied to obtain ionic cross-linked magnetic hydrogel beads. The produced magnetite beads were thoroughly characterized by TEM, SEM/EDS, XRD, FTIR, and VSM techniques. While the water absorbency (WA) of magnetic beads was enhanced by increasing the weight ratio of κ-carrageenan, introducing magnetic nanoparticles caused a decrease in WA capacity from 15.4 to 6.3 g/g. Investigation on the swelling of the hydrogel beads in NaCl, KCl, and CaCl2 solutions revealed the disintegration of beads depending... 

    Semi-IPN carrageenan-based nanocomposite hydrogels: Synthesis and swelling behavior

    , Article Journal of Applied Polymer Science ; Volume 118, Issue 5 , 2010 , Pages 2989-2997 ; 00218995 (ISSN) Mahdavinia, G. R ; Marandi, G. B ; Pourjavadi, A ; Kiani, G ; Sharif University of Technology
    2010
    Abstract
    Inclusion of nano-clays into hydrogels is an efficient approach to produce nanocomposite hydrogels. The introduction of nano-clay into hydrogels causes an increase in water absorbency. In the present work, Nanocomposite hydro-gels based on kappa-carrageenan were synthesized using sodium montmorillonite as nano-clay. Acrylamide and meth-ylenebisacrylamide were used as monomer and crosslinker, respectively. The structure of nanocomposite hydrogels was investigated by XRD and SEM techniques. Swelling behavior of nanocomposite hydrogels was studied by varying clay and carrageenan contents as well as methylenebisacrylamide concentration. An optimum swelling capacity was achieved at 12% of sodium... 

    Synthesis of Novel Biodegradable Collagen-Based Superabsorbent Hydrogels and Investigation of their Swelling Behavior in Various Media

    , Ph.D. Dissertation Sharif University of Technology Salimi,Hamid (Author) ; Pourjavadi, Ali (Supervisor)
    Abstract
    The use of super-swelling polymers is steadily increasing and the applications in industry are continuing to grow. With the authorization of the superabsorbents in food packaging by the Food and Drug Administration recently, demand may soon take off in the market. The worldwide production of SAPs is more than one million tons per year, representing a multibillion-dollar market. However, the increase in prices of petroleum products in recent years may be a drawback for these acrylic-based materials. Thus, there is now a need to develop natural-based super-swelling hydrogels which are more economical and environment friendly. In addition, the super-swelling gels are promising novel functions... 

    Optimized synthesis of carrageenan-graft-poly(sodium acrylate) superabsorbent hydrogel using the Taguchi method and investigation of its metal ion absorption

    , Article Polymer International ; Volume 56, Issue 2 , 2007 , Pages 283-289 ; 09598103 (ISSN) Pourjavadi, A ; Amini Fazl, M. S ; Sharif University of Technology
    2007
    Abstract
    The Taguchi method, a robust experimental design, was used for the optimization of the synthesis of a novel biopolymer-based superabsorbent hydrogel, carrageenan-graft-poly(sodium acrylate). The Taguchi method was applied for the experiment and standard 16 orthogonal arrays with five factors and four levels for each factor were used. In the synthesis of the superabsorbent hydrogel, N,N′-methylene bisacrylamide (MBA) was used as crosslinker, ammonium persulfate as initiator, and acrylic acid as monomer. Neutralization percent and reaction temperature were used as important factors. The analysis of variance results showed that the most important factor in this synthesis was MBA concentration.... 

    Novel highly swelling nanoporous hydrogel based on polysaccharide/protein hybrid backbone

    , Article Journal of Polymer Research ; Volume 18, Issue 3 , 2011 , Pages 337-346 ; 10229760 (ISSN) Bardajee, G. R ; Pourjavadi, A ; Soleyman, R ; Sharif Unviersity of Technology
    2011
    Abstract
    Novel high capacity swelling nanoporous hydrogel (NPH) was synthesized via graft copolymerization of acrylamide (AAm) onto kappa-carrageenan (kC, as a polysaccharide) and gelatin (as a protein) hybrid backbone, after hydrolysis of this system. The Taguchi method as a strong experimental design tool was used for its optimized synthesis. The Taguchi method was applied for the experimental and standard 9 orthogonal array (OA) with four factors and three levels for each factor. A series of NPHs were synthesized by proposed conditions of Qualitek-4 Software. Considering the results of 9 trials according to analysis of variance (ANOVA), optimum conditions were proposed. The swelling behavior of... 

    Reagent-free facile synthesis of silver nanoparticles/nanorods hybrid

    , Article Proceedings of the IASTED International Conference on Nanotechnology and Applications, NANA 2010, 1 November 2010 through 3 November 2010, Cambridge, MA ; 2010 , Pages 498-501 ; 9780889868625 (ISBN) Rezanejade Bardajee, G ; Soleyman, R ; Pourjavadi, A ; Sharif University of Technology
    2010
    Abstract
    Silver nanostructures are very important agents in biomedical research, because of its unique activity against unfavorable processes in bioscience. In the current study, reagent-free facile preparation of silver nanoparticles (average diameter: 72 nm) and silver nanoparticles/ nanorods hybrid was reported via wet chemical synthesis method. Kappa-carrageenan (kC), a hydrophilic biopolymer with sulphate groups on its backbone, as capping agent was used in the reaction medium. Silver nanoparticles and silver nanoparticles/ nanorods formation was confirmed by SEM images. Further investigations were carried out using DLS data and GPC analysis  

    Modified carrageenan. 1. H-CarragPAM, a novel biopolymer-based superabsorbent hydrogel

    , Article Journal of Bioactive and Compatible Polymers ; Volume 20, Issue 5 , 2005 , Pages 475-490 ; 08839115 (ISSN) Hosseinzadeh, H ; Pourjavadi, A ; Mahdavinia, G. R ; Zohuriaan Mehr, M. J ; Sharif University of Technology
    2005
    Abstract
    A novel kappa-carrageenan (κC)-based superabsorbing hydrogel was synthesized through graft copolymerization of acrylamide (AAm) onto a κC substrate in the presence of a crosslinking agent. The crosslinked κC-poly(AAm) polymer graft was partially hydrolyzed in alkaline medium to yield a superabsorbent resin, H-carragPAM. The resin structure was confirmed using FTIR spectroscopy. The variables of graft copolymerization (monomer, initiator, polysaccharide and crosslinker concentration, reaction temperature and time as well as stirrer speed) that affected on the ultimate water-swelling capacity were optimized. The time-temperature variation of the copolymerization was investigated in terms of... 

    γ-irradiation synthesis of a smart hydrogel: Optimization using taguchi method and investigation of its swelling behavior

    , Article Scientia Iranica ; Volume 17, Issue 1 C , June , 2010 , Pages 15-23 ; 10263098 (ISSN) Pourjavadi, A ; Soleyman, R ; Bardajee, Gh. R ; Seidi, F ; Sharif University of Technology
    2010
    Abstract
    In the current work, synthesis of an environmental-sensitive superabsorbent hydrogel using γ-rays is described. Grafted polyacrylonitrile onto a homogeneous solution of starch and kappa-Carrageenan hybrid backbones created a smart material with reversible behavior. The reaction parameters (i.e. acrylonitrile, starch and kappa-Carrageenan concentration, as well as γ-irradiation time) affecting the. water absorbency of the. hydrogel were optimized using the. Taguchi method, in order to achieve a hydrogel with high swelling capacity. FTIR spectroscopy was used for confirming the. structure of the final product and the morphology of the synthesized hydrogel was examined by a scanning electron... 

    Irradiation synthesis of biopolymer-based superabsorbent hydrogel: optimization using the taguchi method and investigation of its swelling behavior

    , Article Advances in Polymer Technology ; Volume 28, Issue 2 , 2009 , Pages 131-140 ; 07306679 (ISSN) Rezanejade Bardajee, G ; Pourjavadi, A ; Soleyman, R ; Sharif University of Technology
    2009
    Abstract
    In this report, the synthesis of a novel superabsorbent hydrogel via γ-irradiation graft copolymerization of acrylamide onto sodium alginate and kappa-carrageenan hybrid backbones in a homogeneous solution is described. The Taguchi method was used as a powerful experimental design tool for synthesis optimization. A series of superabsorbent hydrogels was synthesized by proposed conditions of Qualitek-4 software. Considering the results of nine trials according to analysis of variance, optimum conditions were proposed. The swelling behavior of optimum superabsorbent hydrogels was studied in various solutions, with pH values ranging from 1 to 13. In addition, swelling kinetics, swelling in... 

    New smart carrageenan-based superabsorbent hydrogel hybrid: Investigation of swelling rate and environmental responsiveness

    , Article Journal of Applied Polymer Science ; Volume 117, Issue 6 , September , 2010 , Pages 3228-3238 ; 00218995 (ISSN) Salimi, H ; Pourjavadi, A ; Seidi, F ; Eftekhar Jahromi, P ; Soleyman, R ; Sharif University of Technology
    2010
    Abstract
    Synthesis of novel natural-based superabsorbents with improved properties is of prime importance in many applications. In this article we report an efficient synthesis of new polysaccharide-based superabsorbent hybrid composing carrageenan, acrylic acid, sodium acrylate, and 2-hydroxyethyl acrylate through homogenous solution polymerization process. Infrared spectroscopy and thermogravimetric analysis (TGA) were carried out to confirm the chemical structure of the hydrogel. Moreover, morphology of the samples was examined by scanning electron microscopy (SEM). To deeper studies on the structure-property relation in SAP hydrogels, three hydrogels with different acrylic acid/2-hydroxyethyl... 

    Novel superabsorbent hydrogel based on natural hybrid backbone: optimized synthesis and its swelling behavior

    , Article Bulletin of the Korean Chemical Society ; Volume 30, Issue 11 , 2009 , Pages 2680-2686 ; 02532964 (ISSN) Pourjavadi, A ; Soleyman, R ; Bardajee Rezanejade, G ; Ghavami, S ; Sharif University of Technology
    2009
    Abstract
    The synthesis of a novel superabsorbent hydrogel with natural hybrid backbone via graft copolymerization of acrylamide (AAm) onto kappa-carrageenan (kC, as a polysaccharide) and gelatin (as a protein) under classic thermal conditions is described. The Taguchi method as a strong experimental design tool was used for synthesis optimization. A series of hydrogels were synthesized by proposed conditions of Qualitek-4 Software. Considering the results of 9 trials according to analysis of variance (ANOVA), optimum conditions were proposed. The swelling behavior of optimum hydrogel was measured in various solutions with pH values ranging from 1 to 13. In addition, swelling kinetics, swelling in...