Search for: water-absorbency
0.008 seconds

    Synthesis and investigation of swelling behavior of new agar based superabsorbent hydrogel as a candidate for agrochemical delivery

    , Article Journal of Polymer Research ; Volume 16, Issue 6 , 2009 , Pages 655-665 ; 10229760 (ISSN) Pourjavadi, A ; Farhadpour, B ; Seidi, F ; Sharif University of Technology
    In this investigation a new type of superabsorbent hydrogel based on agar was prepared, and the effect of the feed ratio of some components (acrylic acid, MBA, APS and agar) on the swelling capacity of the hydrogel was systematically studied. Maximum water absorbency of the optimized final product was found to be 1,100∈g/g in distilled water. The structure of the hydrogel was characterized by FT-IR method and morphology of the samples was examined by scanning electron microscopy (SEM). Swelling properties of optimized hydrogel sample in different swelling mediums were investigated. The optimum hydrogel were also loaded with potassium nitrate and its potential for controlled release of... 

    Grafted CMC/silica gel superabsorbent composite: Synthesis and investigation of swelling behavior in various media

    , Article Journal of Applied Polymer Science ; Volume 108, Issue 5 , 2008 , Pages 3281-3290 ; 00218995 (ISSN) Pourjavadi, A ; Seidi, F ; Salimi, H ; Soleyman, R ; Sharif University of Technology
    In the present study, we attempt to synthesize and characterize novel CMC-g-poly (acrylic acid-co-2-acrylamido-2-methylpropanesulfonic acid)/silica gel composite. Infrared spectroscopy and TGA thermal analysis were carried out to confirm the chemical structure of the hydrogel. Moreover, morphology of the samples was examined by scanning electron microscopy. The effect of reaction variables affecting on water absorbency of the composite and swelling behavior in various solvents, salt, and pH solutions was investigated. Maximum water absorbency of the optimized final product was found to be 4000 g/g in distilled water. The absorbency under load (AUL) of the hydrogel was also determined by... 

    Synthesis and characterization of salep sulfate and its utilization in preparation of heavy metal ion adsorbent

    , Article Journal of Applied Polymer Science ; Volume 130, Issue 4 , 2013 , Pages 3001-3008 ; 00218995 (ISSN) Pourjavadi, A ; Doulabi, M ; Alamolhoda, A. A ; Tavakkoli, E ; Amirshekari, S ; Sharif University of Technology
    A multicomponent polysaccharide obtained from dried tubers of certain natural terrestrial orchids was chemically modified by sulfonation using chlorosulfonic acid-dimethylformamide (HClSO3-DMF) complex as a reagent. For a structural characterization of salep sulfate 1H nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) spectra, and Thermogravimetric analysis (TGA) curves were recorded. The sulfate content of modified salep was determined using elemental analysis. This modified biopolymer was used to prepare a new environment-friendly heavy metal ion adsorbent, salep sulfate-graft-polyacrylic acid hydrogel (SS-g-PAA). Swelling rate and equilibrium water absorbency in various... 

    Synthesis and characterization of a novel (salep phosphate)-based hydrogel as a carrier matrix for fertilizer release

    , Article Reactive and Functional Polymers ; Volume 72, Issue 10 , 2012 , Pages 667-672 ; 13815148 (ISSN) Pourjavadi, A ; Doulabi, M ; Soleyman, R ; Sharif, S ; Eghtesadi, S. A ; Sharif University of Technology
    Elsevier  2012
    Salep phosphate modified biopolymers with different phosphate contents were prepared via reacting salep (a multi-component polysaccharide obtained from dried tubers of certain natural terrestrial orchids) with a solution of primary and secondary sodium phosphates under basic conditions in a semidry process. Structural characterization of salep phosphates were carried out by 31P NMR, FT-IR spectra and TGA curves. Determination of the phosphate content in samples was done by a standard spectrophotometric method. Then, novel (salep phosphate)-based hydrogels were synthesized by graft copolymerization of acrylic acid (AA) monomer onto salep phosphate backbones. Effect of the phosphate contents... 

    Salep-g-poly(sodium acrylate)/alumina as an environmental-sensitive biopolymer superabsorbent composite: Synthesis and investigation of its swelling behavior

    , Article Advances in Polymer Technology ; Volume 31, Issue 1 , 2012 , Pages 41-51 ; 07306679 (ISSN) Bardajee, G. R ; Pourjavadi, A ; Soleyman, R ; Ghavami, S ; Sharif University of Technology
    A novel kind of a biopolymer-based superabsorbent composite, salep-g-poly(sodium acrylate)/alumina, was prepared from salep, sodium acrylate, and alumina by aqueous polymerization, using N,N'-methylenebisacrylamide (MBA) as a cross-linker and ammonium persulfate (APS) as an initiator. The reaction parameters [i.e., acrylic acid (AA), MBA, APS amounts, and neutralization percentage of AA as well as alumina/salep weight ratio] affecting the water absorbency of the hydrogel composite were optimized using systematic method to achieve a composite with high swelling capacity as possible. The swelling behavior of optimum superabsorbent composite was measured in various pH solutions. In addition,... 

    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
    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... 

    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
    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... 

    A superabsorbent hydrogel network based on poly ((2-dimethylaminoethyl) methacrylate) and sodium alginate obtained by γ-radiation: Synthesis and characterization

    , Article Iranian Polymer Journal (English Edition) ; Volume 21, Issue 12 , 2012 , Pages 829-836 ; 10261265 (ISSN) Bardajee, G. R ; Hooshyar, Z ; Zehtabi, F ; Pourjavadi, A ; Sharif University of Technology
    In this study, the synthesis and characterization of a novel nano-porous superabsorbent hydrogel with high water swelling capacity is described. A nano-porous hydrogel was prepared by employing (2-dimethylaminoethyl) methacrylate (PDMAEMA) as a pH sensitive monomer and sodium alginate (SA) as a water soluble polysaccharide under γ-ray irradiation. The polymerization reaction was performed at room temperature in the absence of chemically toxic crosslinking agent and initiators. The interactive parameters including biopolymer backbone concentration, monomer concentration and γ-irradiation dose were selected as major factors in the synthesis of superabsorbent and three levels for each factor...