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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) ; Pourjavadi, A ; Soleyman, R ; Ghavami, S ; Sharif University of Technology
Abstract
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,...
Antipolyelectrolyte superabsorbing nanocomposites: synthesis and properties
, Article Journal of Applied Polymer Science ; Volume 114, Issue 6 , 2009 , Pages 3542-3547 ; 00218995 (ISSN) ; Kheirabadi, M ; Zohuriaan Mehr, M. J ; Kabiri, K ; Sharif University of Technology
Abstract
Novel polyampholytic superabsorbing nanocomposites based on the zwitterionic sulfobetaine monomer [3-(methacrylamido)propyl)]dimethyl(3- sulfopropyl)ammonium hydroxide were synthesized through in situ polymerization in aqueous solution with different contents of an organo-modified clay (OMMT, Cloisite 30B). Structural and thermomechanical properties of hydrogels were characterized by FT-IR, XRD, and DMTA, respectively. Swollen gel strength of hydrogels was determined by a rheological method. Storage modulus of the hydrogels was considerably improved in comparison with its the clay-free counterpart. The nanocomposite hydrogel containing 15% OMMT possessed the highest gel strength. The glass...
Effect of pH, citrate treatment and silane-coupling agent concentration on the magnetic, structural and surface properties of functionalized silica-coated iron oxide nanocomposite particles
, Article Physica E: Low-Dimensional Systems and Nanostructures ; Volume 44, Issue 3 , December , 2011 , Pages 618-627 ; 13869477 (ISSN) ; Yaghmaei, S ; Roostaazad, R ; Bardania, H ; Arpanaei, A ; Sharif University of Technology
Abstract
Superparamagnetic iron oxide nanoparticles were synthesized by coprecipitation of iron chloride salts at various pH values (9, 10, 11 and12) that were adjusted using an ammonia solution. Increasing the pH from 9 to 12 led to decreases in the size of iron oxide nanoparticles from 7.9±1.4 to 5±0.6 nm and the saturation magnetization (M s) from 82.73 to 67.14 emu/g, respectively, when analyzed with transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). X-ray diffraction patterns as well as M s values showed that magnetite is the dominantly synthesized phase in the examined pH values. Unmodified iron oxide nanoparticles were coated with silica via the hydrolysis and...