Supercritical antisolvent precipitation was used to obtain ZnO (undoped) and Fe-doped photocatalysts at different Fe/Zn molar ratio percentages (0.57, 0.75 0.84 mol%). Wide-angle X-ray diffraction showed the hexagonal wurtzite as main crystalline phase of cauliflower-like nanoparticle aggregations (observed from Field Emission Scanning Electron Microscopy) with a mean diameter 54.5 nm for pure nanoparticles higher (in range 109.1–121.5 nm) nanoparticles. XRF confirmed approximate ratios...

FeN -co-doped TiO2 photocatalysts are prepared by sol–gel method using titanium tetraisopropoxide, urea and iron(II) acetylacetonate as precursors of titania, nitrogen iron, respectively. The samples analysed from chemical-physical point view X-ray diffraction (XRD), Raman spectroscopy, UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS), specific surface area measurements scanning electron microscopy (FESEM). DRS spectra evidence that the co-doping with N Fe leads to narrowing band gap...

Group 4 metals complexes bearing anilidomethylpyridine ligands have been synthesized and characterized by nuclear magnetic resonance (NMR) spectroscopy, elemental analysis, single-crystal X-ray diffraction analysis. All complexes, after activation using AliBu2H methylalumoxane (MAO) were tested in 1,3-butadiene α-olefins polymerization. The zirconium showed higher activity with respect to the titanium homologous. Polymerization of ethylene resulted, all cases production high molecular weight...

N-doped TiO2 (N-TiO2) and ZnO (N-ZnO) were synthesized utilizing ammonia as a dopant source. The chemico-physical characteristics of samples studied by Raman spectroscopy, X-ray diffraction, SEM analysis, N2 adsorption–desorption at −196 °C, diffuse reflectance spectroscopy. Compared to undoped samples, the introduction nitrogen in semiconductor lattice resulted shift band-gap energy lower value: 3.0 eV for N-ZnO 2.35 N-TiO2. photocatalysts tested degradation Eriochrome Black T (EBT), which...

Monolithic composite aerogel based on a photocatalytic system, constituted by Fe0 (ZVI) coupled with ZnS (FZ), embedded into syndiotactic polystyrene (sPS) matrix was used, for the first time, in lindane degradation under UV light. The content of FZ photocatalyst inside monolithic (FZsPS) 3 wt%. FESEM images FZsPS indicate that is well dispersed polymer matrix. EDS analyses and temperature-programmed reduction (TPR-H2) measurements revealed an interpenetrated structure ZVI phases as presence...

An unprecedented cyclopropanation by cyclopolymerization reaction is presented. In particular, catalytic copolymerization processes of ethene and butadiene lead with high trans selectivity to a complete cyclocopolymerization units. Ethene-based copolymers including cyclopropane cyclopentane rings, which can be relevant polyolefin applications, are obtained yields. Several aspects relative the mechanism this reaction, stereoselectivity, discussed.

Stable free radical polymerization has been used in the controlled synthesis of poly(2,5-bis[(4-butylbenzoyl)oxy]styrene), PBBOS. This "mesogen-jacketed liquid crystalline polymer", which mesogenic units attached directly to backbone a side-on mode, found exhibit thermotropic crystallinity similar more conventional main-chain architectures. PBBOS consistently produced molecular weight distributions below theoretical limiting polydispersity 1.5 calculated for process. Surprisingly, comparison...

In this work, two compounds belonging to the BODIPY family, and previously investigated for their photosensitizing properties, have been bound amino-pendant groups of three random copolymers, with different amounts methyl methacrylate (MMA) 2-(dimethylamino)ethyl (DMAEMA) in backbone. The P(MMA-ran-DMAEMA) copolymers inherently bactericidal activity, due amino DMAEMA quaternized nitrogens bounded BODIPY. Systems consisting filter paper discs coated conjugated were tested on model...

Copolymerizations of ethylene with 1,3-butadiene in the presence catalytic systems based on some C2-symmetric zirconocenes (rac-[CH2(3-R-1-indenyl)2]ZrCl2 where R = −C(CH3)3 (1), −CH(CH3)2 (2), −CH2CH3 (3), −CH3 (4), and −H (5)) are compared. The chemical nature relative amount constitutional comonomer units from butadiene strongly affected by bulkiness substituent positions 3 3'. DFT calculations indicate that observed dependence alkyl ligand can be easily rationalized occurrence an unusual...

Unprecedented 1,1 and 1,3 constitutional units from 1,3-butadiene, both presenting only the E configuration of double bond, have been achieved by copolymerization with ethene, conducted at high temperature low ethene concentration, when catalyzed a highly hindered C(2) symmetric metallocene. Ethene/butadiene copolymerizations this catalyst generally lead to prevailing methylene-1,2-cyclopropane butadiene. Polymer microstructures obtained for different comonomer concentrations clearly...

The synthesis and the microstructural characterization of isotactic poly ( N ‐pentenyl‐carbazole) i ‐PPK) are reported. achieved polymer is semicrystalline, melting temperature 138°C. ‐PPK Fourier transform infrared spectroscopy (FTIR) spectrum X‐ray diffraction pattern compared with those polyvinylcarbazole. observed differences tentatively associated to higher flexibility chains due alkylene group connecting carbazole main chain. presence intrachain interchain interactions between units,...

The electroluminescence (EL) of isotactic and syndiotactic poly(N-pentenyl-carbazole) (PPK), achieved by coordination polymerization, is studied in order to investigate the interrelation between polymer tacticity their physical-chemical properties. use these polymers organic light-emitting diode (OLED) fabrication also explored. Thermal x-ray diffraction analyses PPKs show that stereoisomer semicrystalline, whereas one amorphous. Optical analysis both stereoisomers, carried out on film...

ABSTRACT Stereoregular polymers like isotactic poly( N ‐butenyl‐carbazole) ( i ‐PBK), and syndiotactic ‐pentenyl‐carbazole) ‐PPK s ‐PPK), ‐hexenyl‐carbazole) ‐PHK ‐PHK) are synthesized using the stereospecific homogeneous “single site” Ziegler‐Natta (Z‐N) catalysts: rac ‐dimethylsilylbis(1‐indenyl)zirconium dichloride 1 )/methylaluminoxane (MAO) diphenylmethylidene(cyclopentadienyl)‐(9‐fluorenyl)zirconium 2 )/MAO. Catalytic activity is rationalized by density functional theory (DFT)...

Different tri-doped TiO2 photocatalysts (Fe-N-P/TiO2, Fe-N-S/TiO2, Fe-Pr-N/TiO2, Pr-N-S/TiO2, and P-N-S/TiO2) were successfully prepared tested in the photocatalytic removal of thiacloprid (THI) under UV-A, visible, direct solar light irradiation. The physical-chemical properties catalysts analyzed by different characterization techniques, revealing that dopants are effectively incorporated into anatase lattice, resulting a decrease energy band gap. reduction photoluminescence intensity...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMesomorphism in Segmented-Chain Polymers Containing Flexible Substituents the Rigid MoietyUgo Caruso, Stefania Pragliola, Antonio Roviello, Augusto Sirigu, and Pio IannelliCite this: Macromolecules 1995, 28, 18, 6089–6094Publication Date (Print):August 1, 1995Publication History Published online1 May 2002Published inissue 1 August 1995https://pubs.acs.org/doi/10.1021/ma00122a014https://doi.org/10.1021/ma00122a014research-articleACS...

ADVERTISEMENT RETURN TO ISSUEPREVNoteEthene/1,3-Butadiene Copolymerization in the Presence of rac-(CH2-(3-tert-butyl-1-indenyl)2)ZrCl2/MAO Catalytic System: Study Polymerization Mechanism by Using 13C-Labeled 1,3-ButadieneStefania Pragliola, Chiara Costabile, Mariateresa Magrino, Mariagrazia Napoli, and Pasquale LongoView Author Information Dipartimento di Chimica, Università Salerno, Via Allende, 80184 Baronissi (SA), Italy Cite this: Macromolecules 2004, 37, 1, 238–240Publication Date...

The synthesis of isotactic poly(N-butenyl-carbazole) (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mrow><mml:mi>i</mml:mi></mml:mrow></mml:math>-PBK) by using homogeneous isospecific Ziegler-Natta catalytic system is reported. achieved polymer crystalline and shows, to DSC X-ray analysis, two distinct phases.<mml:math id="M2"><mml:mrow><mml:mi>i</mml:mi></mml:mrow></mml:math>-PBK FTIR spectrum diffraction pattern are compared with those poly(N-vinylcarbazole) (PVK)....

Poly-L-lactic acid (PLLA) aerogel-based scaffolds were obtained from physical PLLA gels containing cyclopentanone (CPO) or methyl benzoate (BzOMe) molecules. An innovative single step method of solvent extraction, using supercritical CO2, was used to achieve cylindrical monolithic aerogels. The pore distribution and size, analyzed by SEM microscopy, found be related the crystalline forms present in nodes that hold together, stable α'-form metastable co-crystalline ε-form, detected PLLA/BzOMe...