Fakhreia Al Sagheer

Radiation-induced graft polymerization of acrylic acid onto poly(tetrafluoroethylene-perfluorovinyl ether) copolymer films: complexation with some transition metals and biological activity

Abstract The radiation-induced grafting of acrylic acid onto poly(tetrafluoroethylene-perfluorovinyl ether) copolymer film was carried out to synthesize graft copolymer membranes of complexing ability with some selected transition metal ions such as Cr III , Mn II , Cu II , Ag I and Cd II . The complex formation of these graft copolymer–metal complexes was studied by atomic absorption spectroscopy, X-ray fluorescence, IR, UV and electron spin resonance spectrometry. The overall results suggest octahedral geometry for both Cr III and Mn II but square planar for Cu II . The results revealed the high stability of the obtained ligand–metal complexes. The biological activity of the grafted film and its complexes with various metal ions was investigated under the same conditions. Silver (I) complexed membrane had a strong biocidal effect for all tested bacteria. The biological activity for Cr III complex has been effected on E . coli and S . aureus , whereas the Cd II complex has its effect on E . coli , B . anthrax and B . cereus . The Cu II complex has only antifungal activity. No biological effect has appeared for both the grafted film or Mn II complexed one on either bacteria or fungi.

Investigation of radiation‐grafted and radiation‐modified N‐vinyl‐2‐pyrrolidone onto polypropylene film

The radiation-induced graft copolymerization of N-vinyl-2-pyrrolidone (NVP) onto polypropylene films was investigated using the mutual method. The grafted polymer was modified with prepared α,β-unsaturated nitrile (Scheme 1). The water uptake of the grafted and modified grafted films was found to increase with the degree of grafting. It was observed that the swelling behavior of the modified grafted films with α-cyano-β-phenyl crotononitrile improved more than that of the film grafted and modified grafted with α-cyano-β-(2-thienyl)crotononitrile or α-cyano-β-(2-pyridyl)crotononitrile. The modification process for the grafted substrate was confirmed by IR spectroscopy. No significant improvement was observed in thermal stability for the modified grafted films compared to the grafted films. Scanning electron microscopy (SEM) of the grafted and modified grafted membranes heated to 150°C showed change in the structure and morphology. Improvement in the hydrophilicity and morphology of these membranes with carbonitriles may increase the permeability of those membranes for some practical applications.

Some investigations on radiation‐grafting of acrylic acid onto poly(tetrafluoroethylene–ethylene) copolymer films and its complex with copper salt solution

A study was made of the graft copolymers obtained by radiation-induced grafting of acrylic acid onto poly(tetrafluoroethylene–ethylene) (ET) films. The conversion of the graft copolymers (60wt%) into metal acrylate copolymer complexes was carried out by treatment with various concentrations of aqueous CuCl2. These graft copolymer–metal complexes were studied by IR, UV spectrometry, X-ray diffraction (XDR), and electron spin resonance (ESR). The effect of temperature on the trunk, untreated grafted and treated grafted copolymer films was investigated by IR and thermogravimetric (TG) analysis. The influence of metal complexes of Cu2+ ions on the thermal properties and electrical conductivity was determined. It is assumed that such materials may be of great interest in the field of semiconducting materials, in addition to their resistance to degradation under high temperature, up to 300°C.

Polymerization behaviour of a new vinyl thiourea derivative

Abstract 1-Methacryloyl-3-phenylthiourea (MAPTU) has been prepared and polymerized by a free-radical mechanism. The polymer formed has low molecular weight. The kinetic orders of the polymerization with respect to monomer and initiator, as well as the overall activation energy, were measured and found to be those expected for a free-radical scheme. This new monomer showed a tendency for cyclization to give a six-membered heterocycle. The effects of temperature and solvent on the rate of cyclization have been studied. MAPTU monomer and its homopolymer were found to form complexes with several metal ions. The stability constants of several phenyl-substituted MAPTU with Cu were measured and a correlation between log K X K H and the Hammett constant was established. The MAPTU-Cu and polyMAPTU-Cu complexes were prepared and their stability constants were calculated. MAPTU was copolymerized with styrene and acrylonitrile. The reactivity ratios have been calculated by several methods.

Au/ZnS and Ag/ZnS nanoheterostructures as regenerated nanophotocatalysts for photocatalytic degradation of organic dyes

Although several groups have reported the synthesis of ZnS quantum dots, only a few have developed methods to prepare potentially nontoxic, noble metal loaded ZnS QDs. In this study, we devised a gram scale, environmentally benign, room temperature, aqueous solution based method for the synthesis of renewable and eco-friendly, well dispersed ZnS quantum dots along with noble metal loaded ZnS QDs (loading amount 4 wt%). The properties of the nanophotocatalysts were determined by using XRD, XPS, TEM and SEM techniques. The ZnS QDs were found to have small sizes of ca. 4.5 nm and to display quantum effects in terms of blue shifts in their absorption maxima associated with an optical band gap, Eg, of 4.63 eV. The photocatalytic activities of ZnS QDs, Au/ZnS and Ag/ZnS were assessed using photodegradation of methylene blue. The results demonstrate that a significant increase in the photocatalytic efficiency takes place upon the loading of Ag and Au nanoparticles on ZnS QDs. An in-depth investigation was carried out to uncover information about the effects of noble metals on band gap energies and surface charges of the QDs. Finally, a new surface reactivation procedure was developed for the reactivation of nanophotocatalysts. Consequently, the newly synthesized photocatalysts are renewable, a property that should make their use in practical applications cost effective.

Synthesis and characterization of polysulfanilamide and its copolymers: bioactivity and drug release

Sulfanilamide reacted with acryloyl chloride to give 4-(N-acrylamido)benzenesulfonamide (ABA), which converted to the corresponding polymer (PABA) upon treatment with initiator at 75°C. Various copolymers formed from ABA with acrylamide (AA), acrylonitrile (AN), and N-(thiazol-2-yl)acrylamide (TA) at different ratios (50 : 50, 70 : 30 and 30 : 70) were prepared. The polymer and copolymers were characterized using IR, 1H NMR, 13C NMR and mass spectroscopy, thermogravimetry, and scanning electron microscopy. The drug release from polymeric chain and copolymers was studied at 37°C and pH 8.4. The drug release was highly increased upon adding sodium chloride at various concentrations, 0.1%, 0.5% and 0.9%. The drug release from the polymer and copolymer chains was measured using a UV-visible spectroscopy technique. Antimicrobial activity of the polymer and copolymers was studied. It is established that the ABA copolymer with TA is more effective as compared to other copolymers.

Non-noble, efficient catalyst of unsupported α-Cr 2 O 3 nanoparticles for low temperature CO Oxidation

Herein, we report the synthesis of chromium oxide nanoparticles, α -Cr2O3 NPs, followed by full characterization via XRD, SEM, XPS, and N2 sorptiometry. The synthesized nanoparticles were tested as catalysts toward the oxidation of CO. The impact of calcination temperature on the catalytic activity was also investigated. CO conversion (%), light-off temperature, T50, data were determined. The results revealed that chromia obtained at low calcination temperature (400 °C) is more active than those obtained at high calcination temperatures (600° or 800 °C) and this is ascribed to the smaller particle size and higher surface area of this sample. The results revealed a superior catalytic activity of Cr2O3 NPs at lower temperature as we reached a complete conversion at 200 °C which is high value in the forefront of the published results of other non-noble catalysts. The high activity of Cr2O3 nanoparticles (T50 as low as 98 °C) where found to be dependent on a careful selection of the calcination temperature. These results may provide effective and economic solutions to overcome one of the major environmental threats.

Convenient synthesis and antibacterial activity of tricyclic azine derivatives

1,4-Phenylenediamine reacted readily with 2 mol of ethyl acetoacetate to give diethyl (2Z,2′Z)-3,3′-[(1,4-phenylene)-bisimino]dibut-2-enoate, which reacted with dimethylformamide dimethylacetal, activated methylene nitriles, ylidenemalononitriles and phenyl and benzoyl isothiocyanate to give, respectively, a 4,7-phenanthroline-2,9-dicarb-oxylate-1,10-diol, and tricyclic bispyridine and bispyrimidine derivatives. Two compounds showed strong antibacterial activity against several microorganisms, while six others showed high to moderate activity.

Controlled Synthesis of ZrO 2 Nanoparticles with Tailored Size, Morphology and Crystal Phases via Organic/Inorganic Hybrid Films

In this investigation, well defined mesoporous zirconia nanoparticles (ZrO2 NPs) with cubic, tetragonal or monoclinic pure phase were synthesized via thermal recovery (in air) from chitosan (CS)- or polyvinyl alcohol (PVA)-ZrOx hybrid films, prepared using sol–gel processing. This facile preparative method was found to lead to an almost quantitative recovery of the ZrOx content of the film in the form of ZrO2 NPs. Impacts of the thermal recovery temperature (450, 800 and 1100 °C) and polymer type (natural bio-waste CS or synthetic PVA) used in fabricating the organic/inorganic hybrid films on bulk and surface characteristics of the recovered NPs were probed by means of X-ray diffractometry and photoelectron spectroscopy, FT-IR and Laser Raman spectroscopy, transmission electron and atomic force microscopy, and N2 sorptiometry. Results obtained showed that the method applied facilates control over the size (6–30 nm) and shape (from loose cubes to agglomerates) of the recovered NPs and, hence, the bulk crystalline phase composition and the surface area (144–52 m2/g) and mesopore size (23–10 nm) and volume (0.31–0.11 cm3/g) of the resulting zirconias.

High-temperature stable transition aluminas nanoparticles recovered from sol–gel processed chitosan-AlO x organic–inorganic hybrid films

AbstractFive and ten weight percent-alumina-containing chitosan-AlOx films were prepared via sol–gel processing. The films were AlOx-agglomerate-free. These organic–inorganic films were degraded by heating at 500 °C. The solid powder residues were found by means of thermogravimetry, X-ray diffractometry, infrared spectroscopy, and electron microscopy to consist of alumina (Al2O3) nanoparticles entraping volatile components, whose thermal removal encouraged ambient oxygen uptake. The surface microstructure and morphology of the recovered alumina nanoparticle were inspected by high-resolution transmission and scanning electron microscopy. Also, the surface chemistry and texture were evaluated by X-ray photoelectron spectroscopy and N2 sorptiometry. Coalescences of globular nanoparticles of γ-/η-Al2O3 were the dominant composition of the 800 °C calcination product of the recovered alumina, irrespective of the alumina-content of the film. Upon increasing the calcination temperature up to 1100 °C, an enhanced polymorphic transition into agglomerated nanoparticles of the seldom encountered Iota-(ι-)Al2O3 took place. The high thermal stability of the otherwise unstable transition aluminas (at ≥950 °C) may suggestively owe to its polymorphic interdependence and/or persistent nanoscopic nature (average particle size = ca. 3–4 nm; specific surface area = ca. 80–60 m2/g). The surface chemical composition for the recovered transition aluminas nanopowders promises versatile acid–base properties for catalysis applications. Accordingly, the highly abundant bio-waste, chitosan, was successfully utilized as a novel synthesis medium for catalytic-grade alumina nanoparticles. The highly abundant bio-waste material, chitosan, is successfully employed as a synthetic medium for catalytic-grade alumina nanoparticles. This novel sol–gel synthesis process resulted in nearly 100%-recovery of nanoparticle transition γ-/η- and ι-Al2O3 and may be utilized in fabricating other materials/metal oxides