Time filter

Source Type

Raafat A.I.,National Center for Radiation Research And Technology
Journal of Applied Polymer Science | Year: 2010

Based on gelatin (Gltn) and acrylic acid (AAc), biodegradable pH-sensitive hydrogel was prepared using gamma radiation as super clean source for polymerization and crosslinking. Incorporation of PAAc in the prepared hydrogel was confirmed by Fourier transform infrared spectroscopy (FTIR). The effect of PAAc content on the morphological structure of the prepared hydrogel swollen at pH 1, 5, and 7 was examined using scanning electron microscopy (SEM). The results showed the dependence of the porous structure of the prepared hydrogels on AAc content and the pH of the swelling medium. Swelling properties of gelatin/acrylic acid copolymer hydrogels with different AAc contents were investigated at different pH values. Swelling data showed that the prepared hydrogels possessed pronounced pH sensitivity. In vitro release studies were performed to evaluate the hydrogel potential as drug carrier using ketoprofen as a model drug. Experimental data showed that the release profile depends on both hydrogel composition and pH of the releasing medium. © 2010 Wiley Periodicals.

Mahmoud G.A.,National Center for Radiation Research And Technology
Monatshefte fur Chemie | Year: 2013

Hydrogels based on acrylamide and 2-acrylamido-2-methyl-1-propanesulfonic acid were synthesized via a gamma irradiation technique and used for preparation of magnetic responsive hydrogels. The hydrogels obtained were investigated by means of X-ray diffraction, Fourier-transform infrared (FT-IR), magnetic properties, thermogravimetric analysis, and energy-dispersive X-ray analysis. The extent of adsorption was investigated as a function of pH of medium, initial metal ion concentration, and contact time. The adsorption process was well described by pseudo-second-order kinetics, and the best interpretation of the equilibrium data was given by the Freundlich isotherm. The results from sequential adsorption-desorption cycles showed that the hydrogel exhibited good desorption and reusability. It was revealed that such hydrogel networks with magnetic properties can be effectively utilized for removal of pollutants and adsorbed heavy-metal ions. The maximum adsorption capacities were 321, 436, and 470 mg g-1 for Pb(II), Cd(II), and Cu(II) ions, respectively. © 2013 Springer-Verlag Wien.

Eid M.,National Center for Radiation Research And Technology
Journal of Inorganic and Organometallic Polymers and Materials | Year: 2011

Starch based polyelectrolyte hydrogels are composed of combination of starch with N-vinyl pyrrolidone (NVP), acrylamide (AAm) and acrylic acid (AAc). The Starch based polyelectrolyte hydrogels were successfully synthesized by using gamma radiation polymerization technique. Silver nanopaticles were formed by reduction of silver nitrate in the hydrogels with sodium borohydride under room temperature. The formation of silver nanoparticles in hydrogels were well characterized by using Fourier-transform infrared (FTIR), UV-Visible spectroscopy, X-ray diffraction studies transmission electron microscope (TEM) and scanning electron microscopy (SEM) studies. The X-ray diffraction analysis confirmed the formation of silver nanoparticles in the range of 38.86, 41.44 and 47.07 nm for P(Starch/NVP)-Ag, P(Starch/AAm)-Ag and P(Starch/AAc)-Ag nanoparticles hydrogels, respectively. The TEM images supported the mean size particle of 35.81, 39.29 and 40.45 nm for P(Starch/NVP)-Ag, P(Starch/AAm)-Ag and P(Starch/AAc)-Ag, respectively. The SEM images indicated clearly the formation of silver nanoparticles with spherical shape within the network of the hydrogels. © 2010 Springer Science+Business Media, LLC.

El-Nemr K.F.,National Center for Radiation Research And Technology
Materials and Design | Year: 2011

In the present study, the effect of different curing systems including sulfur, dicumyl peroxide, dicumyl peroxide/coagent and radiation/coagent on the mechanical and physico-chemical properties of acrylonitrile butadiene rubber (NBR) was studied. In order to correlate, the effect of curing systems on rubber, the comparison was carried out at comparable value of volume fraction of rubber in swollen gel (Vr) for NBR vulcanizates. Mechanical properties like tensile strength, elongation at break, modulus, Young's modulus, tearing strength and abrasion loss of vulcanizates have been followed up for comparison. In addition, physico-chemical properties like swelling ratio, soluble fraction, and cross-link density were investigated. On the other hand, the effects of fuel, thermogravimetric analysis, and thermal ageing have been studied. © 2011 Elsevier Ltd.

Eid M.,National Center for Radiation Research And Technology
Journal of Polymer Research | Year: 2013

Hydroxyethyl methacryate (HEMA)-Agar and Hydroxyethyl methacryate (HEMA)-Gelatin hydrogels have been prepared by gamma radiation as polymeric stabilizer for magnetic nanoparticles via radiation technique and loading co-precipitation technique. The swelling property of the prepared hydrogels in bidistilled water and different pH's was studied and the results showed that, the swelling percent of the plain hydrogel was found to be higher for all different compositions. The morphology and structure of the prepared hydrogels and dispersion of the magnetic nanoparticles in the hydrogel network were examined by Scanning electron microscopy (SEM) and Infrared spectroscopy (FT-IR). The particle size of the formed magnetic nanoparticles has been confirmed by Dynamic light scattering (DLS) and Transmission electron microscope (TEM), and it was found to be smaller in loading co-precipitation technique than irradiation technique. The HEMA-Gelatin-Fe3O4 has higher particle size than HEMA-Agar-Fe3O4 (HAF). Finally, the drug loading capacities of the magnetic nanoparticles and their releasing dependence on different pH were investigated with doxorubicin hydrochloride (DOX) as an anticancer drug model. © 2013 Springer Science+Business Media Dordrecht.

Madani M.,National Center for Radiation Research And Technology
Current Applied Physics | Year: 2011

Methyl methacrylate (MMA) monomer was grafted onto Low density Polyethylene by the direct method of radiation grafting. The effect of cohesive energy density of different organic solvents on the degree of grafting was investigated. It was found that the extent of grafting depends largely on the kind of solvent, in which the highest degree of grafting was achieved in the presence of dioxane, whereas the lowest degree of grafting occurred in the presence of methanol. This behaviour was attributed to the solubility parameters of the solvent, monomer and polymer. The change in structure of the LDPE graft copolymer films was characterized by scanning electron microscopy, X-ray diffraction, UV/vis absorption and thermogravimetric analysis. The X-ray diffraction results showed a decrease in the crystallinity of LDPE graft copolymer matrix at high degree of grafting. Studies were made on the UV-absorption edge, indirect allowed transitions with their optical energy gaps are determined. At the same time the Urbach energy was evaluated. The activation energy of the thermal decomposition was calculated according to Horowitz and Metzger method. © 2010 Elsevier B.V. All rights reserved.

Magida M.M.,National Center for Radiation Research And Technology
Journal of Applied Polymer Science | Year: 2012

Polymethylmethacrylate (PMMA) and bisphenol-A-polycarbonate (PC) polymer blends are prepared by solution casting technique using tetrahydrofuran as a solvent. The structural properties of the polymer blends before and after they had been irradiated to electron beam accelerator was investigated by color strength, scanning electron microscopy (SEM), and FTIR spectroscopy. The thermal properties such as TGA and DSC were investigated. The TGA thermograms showed that the thermal stability of the unirradiated polymer blends PMMA/PC increases with increasing the ratios of PC component in the blend. Also, it was found that the presence of PC polymer in the blend affords protection against radiation degradation and improves their thermal stability. The DSC scans show a single T g intermediate between PMMA and PC indicate the existence of specific interactions between PMMA and PC polymers in the blend. An intimate blends are reflected by substantial shifts in the frequencies of the PMMA and PC C=O vibration obtained by FTIR. SEM confirms the homogeneity of the blend. © 2012 Wiley Periodicals, Inc.

El-Hag Ali A.,National Center for Radiation Research And Technology
Journal of Applied Polymer Science | Year: 2012

A series of functional copolymer hydrogels composed of carboxymethyl cellulose (CMC) and 2-acrylamido-2-methyl propane sulfonic acid (AMPS) were synthesized using γ-radiations-induced copolymerization and crosslinking. Preparation conditions were optimized, and the swelling characteristics were investigated. The ability of the prepared hydrogels to recover some toxic metal ions from their aqueous solutions was studied. The prepared hydrogel showed a great capability to recover metal ions such as: Mn+2, Co +2, Cu+2, and Fe+3 from their solutions. The data revealed that the chelating ability of the prepared hydrogels is mainly dependent on their internal composition, in addition to the physical properties of the metal ion solution such as pH and metal ion concentration. The data show that the chelating ability of the prepared hydrogels increases by increasing the AMPS content in the hydrogel as well as the increment in the pH of the solution and the metal ion concentration. The prepared CMC/AMPS copolymer hydrogels are chemically stable enough to be reused for at least five times with the same efficiency. © 2011 Wiley Periodicals, Inc.

Mohamed R.M.,National Center for Radiation Research And Technology
Journal of Industrial and Engineering Chemistry | Year: 2013

Nanocomposites of two different kinds of rubber (acrylonitrile-butadiene rubber NBR and styrene butadiene rubber SBR)/organo-montmorillonite nanocomposites modified by hexadecyltrimethyl ammonium bromide were prepared by the reactive mixing intercalation method in the presence of trimethylolpropane trimethylmethacrylate (TMPTMA). The influence of gamma irradiation on the morphology and properties of the rubber nanocomposites was investigated. Intercalated polar or unsaturated matrices (e.g., NBR and SBR)/OMMT nanocomposites can be obtained, which was confirmed by X-ray diffraction (XRD). The clay layers could be uniformly dispersed in the rubber matrix on the nanometer level. Mechanical tests showed that the nanocomposites had good mechanical properties as compared to the neat composites. The results also showed that the irradiated NBR/OMMT nanocomposites had higher thermal stabilities than irradiated SBR/OMMT nanocomposites. © 2012 The Korean Society of Industrial and Engineering Chemistry.

Hassan M.S.,National Center for Radiation Research And Technology
Radiation Physics and Chemistry | Year: 2015

Jute fibers were grafted with acrylic acid by gamma irradiation technique. Chitosan was immobilized upon the grafted Jute fibers to be used as an adsorbent for waste reactive dye. The treated Jute fibers were characterized by using of Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effect of Jute treatment on its thermal stability by using thermogravimetric analysis (TGA) and its mechanical properties were investigated. The adsorption isotherm and the different factors affecting the dye adsorption such as pH and contact time were also studied. It was found that the dye adsorption was enhanced in the low pH range and increased with increasing of the contact time, regardless of temperature change. © 2015.

Loading National Center for Radiation Research And Technology collaborators
Loading National Center for Radiation Research And Technology collaborators