Sharif Digital Repository

Fast-swelling highly porous superabsorbent hydrogels were synthesized through a rapid radical polymerization under normal atmospheric conditions. To synthesize a biopolymer-based superabsorbent hydrogel, 2-hydroxyethyl acrylate (HEA) and sodium acrylate (AANa) were grafted on the starch backbone in an aqueous solution. The graft copolymerization reaction was carried out in the presence of ammonium persulfate (APS) as an initiator and N, N′-methylenebisacrylamide (MBA) as a cross-linker in a homogeneous medium. The chemical structure of the hydrogels was confirmed by FT-IR spectroscopy and thermogravimetric analysis (TGA). The morphology of the samples was examined by scanning electron... 

A novel and smart biopolymer-based hydrogel was synthesized by graft copolymerization of acrylic acid onto the salep backbones. The new superabsorbent hydrogel was synthesized via simultaneous crosslinking and graft copolymerization of acrylic acid (AA) monomer onto salep backbones using radiochemical methods. In radiochemical methods, γ-rays as initiator, energy source and crosslinker are applied. In our experiments, the effects of reaction variables such as relative contents of salep and AA, as well as γ-rays total dose were examined. According to water absorbency of the entitled network, the best synthesis condition is reported. FTIR spectroscopy, SEM photograph and TGA analysis were used... 

This article describes the synthesis and swelling properties of a superabsorbing hydrogel composite based on collagen. The composite have been prepared via graft copolymerization of acrylic acid (AA) in the presence of kaolin powder using methylenebisacrylamide (MBA) as a crosslinking agent and ammonium persulfate (APS) as an initiator. The certain variables of the graft copolymerization (i.e. the monomer, the initiator, and the crosslinker concentration as well as kaolin/collagen weight ratio) affected on the ultimate water-swelling capacity were optimized. Evidence of grafting and kaolin interaction was obtained by comparison of FTIR spectra of initial substrates and superabsorbent... 

Graft copolymerization of mixtures of acrylic acid (AA) and acrylamide (AAm) onto chitosan was carried out by using potassium persulfate (KPS) as a free radical initiator in the presence of methylenebisacrylamide (MBA) as a crosslinker. The effect of reaction variables, such as MBA concentration and AA/AAm ratio on the water absorbency capacity have been investigated. The polymer structures were confirmed by FTIR spectroscopy. Water absorbencies were compared for the hydrogels before and after alkaline hydrolysis. In the non-hydrolyzed hydrogel, enhanced water absorbency was obtained with increasing AA in monomer feed. However, after saponification, the sample with high AAm ratio exhibited... 

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... 

In this study, we attempt to synthesize novel acrylated agarose (ACAG)-based hydrogels with three different crosslinking densities. Acrylate groups were inserted onto agarose (AG) backbone through homogeneous reaction of acrylic monomers with AG backbone. Hydrogels were synthesized through radical copolymerization of a mixture of acrylic acid and 2-hydroxyethyl acrylate with ACAG in aqueous solution using ammonium persulfate as an initiator. Infrared spectroscopy (FTIR) was carried out to confirm the chemical structure of the hydrogel. Moreover, morphology of the samples was assessed by scanning electron microscopy. The equilibrium swelling capacities of synthesized hydrogels were evaluated... 

In the present work, synthesis and swellability of acrylatedstarch-based hydrogels was investigated. Acrylic groups were introduced onto starch backbone by a homogeneous synthesis to produce starch monomers with three different degree of substitution (DS). The radical copolymerization of acrylatedstarch (AST) with acrylic acid (AA) and acrylamide (AAm) was carried out in aqueous solution using ammonium persulfate (APS) as an initiator. Infrared spectroscopy (FT-IR) 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 (SEM). Their equilibrium swelling degree was evaluated... 

A solvent-free procedure for the synthesis of several 1-aryl-2-(dialkylaminomethyl)-prop-2-en-1-ones 3 (a-e) and 4 (a-e) is reported. Reaction of arylmethyl ketones with formaldehyde and dialkylamines, such as diethyl- or dibutylamines at room temperature in silica gel produce 3 and 4 with moderate yields  

This paper deals with obtaining aromatherapic textiles via applying stimuli-responsive poly N-isopropyl acryl amide (PNIPAAm) chitosan (PNCS) nano hydrogels containing cinnamon oil on cotton fabric and looks into the treated fabric characteristics as an antibacterial and temperaturepH responsive fabric. The semi-batch surfactant-free dispersion polymerization method was proposed to the synthesis of PNCS nano particles. The incorporation of modified β -cyclodextrin ( β-CD) into the PNCS nanohydrogel was performed in order to prepare a hydrophobic(cinnamon oil) carrier embedded in stimuli-responsive nanohydrogel. The β -CD postloading process of cinnamon oil in to the hydrogel nano particles... 

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... 

We demonstrated a novel mixed-matrix composite membrane (MMCM) based on acrylated polyurethane (APU) and UiO-66 nanoparticles to separate CO 2 /N 2 mixture. UiO-66 and functionalized UiO-66 including NH 2 -UiO-66 and glycidyl methacrylate (GMA)-UiO-66 were loaded into APU/2-hydroxyethyl methacrylate (APUH) matrix at variable concentrations between 3 and 30 wt %. APUH/GMA-UiO-66 MMCMs exhibited strong adhesion with a support layer of polyester/polysulfone, which was not deteriorated after immersion in water for a long time (20 days). Incorporation of UiO-66 and its functionalized forms increased simultaneously permeability and CO 2 /N 2 selectivity, which were indeed superior in comparison... 

A series of biodegradable acrylic terminated polyurethanes (APUs) based on poly(ε-caprolactone) diol (PCL), aliphatic 1,6-hexamethylene diisocyanate (HDI) and hydroxyethyl methyl acrylate (HEMA) was synthesized as potential materials for hard tissue biomedical applications. PCLs with low molecular weights of 1000 and 2000 g/mol were employed to provide different amounts of end capped urethane acrylate in APUs. To control crosslink density, a mixture of two different reactive diluents including mono-functional HEMA and bi-functional ethylene glycol dimethacrylate (EGDMA) with different weight ratios was incorporated into the APUs, called here PUAs. Morphological characteristics and mechanical... 

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... 

The synthesis and swelling behavior of a new superabsorbent hydrogel based on natural salep grafted with polyacrylamide is described. The new biopolymer was synthesized via simultaneous crosslinking and graft copolymerization of acrylamide monomer onto a salep backbone using radiochemical methods. Various parameters such as relative contents of salep and acrylamide, as well as total dose of γ-rays were examined. The best synthesis condition is reported and a mechanism for superabsorbent hydrogel formation suggested. Factors affecting the swelling behavior of hydrogel were also studied. © 2008 Elsevier B.V. All rights reserved