Ethylene Polymerization
Mostrando 1-12 de 60 artigos, teses e dissertações.
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1. Antimicrobial High-Density Polyethylene (HDPE)/ZnO Nanocomposites Obtained by in situ Polymerization
Nanostructured zinc oxide (ZnO) prepared by combustion in solution was used to obtain nanocomposites. The ZnO particles were characterized by Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), and scanning electron microscopy (SEM), showing crystallite size of 32 nm and a superficial area of 32.6 m2 g-1. Nanocomposites with 1, 3, and 5 wt.% of ZnO in the
J. Braz. Chem. Soc.. Publicado em: 2020-08
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2. DINÂMICA MOLECULAR REATIVA DA ABERTURA DO ANEL EPÓXI EM REAÇÕES COM POLIAMINA Ellen
The molecular dynamics simulations were used to study the epoxy ring-opening in the determination of kinetic parameters, with a temperature range from 1500 to 2500 K in a 20 x 20 x 20 Å unit cell containing 15 molecules of C2H4O (ethylene oxide) and 35 molecules of CH6N2 (methanediamine). The activation energy values for epoxy and diamine was 66 and 92 kJ m
Quím. Nova. Publicado em: 2020-05
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3. Application of a Novel Ion-Imprinted Polymer to the Separation of Traces of CdII Ions in Natural Water: Optimization by Box-Behnken Design
This study describes the preparation of a novel ion-imprinted polymer (IIP) to apply pre-concentration of cadmium ions in water samples of the Pontal Bay in Ilhéus, Brazil. First, cadmium ion was complexed with 2-(2-thiazolylazo)-p-cresol (TAC). Subsequently, there was the polymerization using ethylene glycol dimethacrylate and methacrylic acid monomers alo
J. Braz. Chem. Soc.. Publicado em: 2019-04
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4. ETHYLENE POLYMERIZATION WITH NICKEL DIIMINE COMPLEXES CONTAINING PSEUDOHALIDES
Nickel-diimine complexes DADNiX2 (DAD= 2,6-iPr2-C6H3-N=C(Me)-C(Me)=N-2,6-iPr2-C6H3) containing the non-chelating pseudo-halide ligands isothyocyanate and isoseleniumcyanate (X= NCS 1 and NCSe 2) were synthesized and used in ethylene polymerization activated by methyaluminoxane (MAO) at temperatures from 0 to 50°C. Polymerizations with these complexes were c
Quím. Nova. Publicado em: 2018-07
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5. Preparation and Performance of an Estradiol Templated Magnetic Sphere of Molecularly Imprinted Cryogel
An estradiol templated core-shell magnetic molecularly imprinted cryogel (MMIC) was synthesized to selectively extract and analyze estradiol in milk powder. The microsphere of Fe3O4@SiO2 was firstly prepared on Fe3O4 with ethyl silicate and 3-methyl propyl trimethoxy silane. Then the polymerization of α-methacrylic acid and ethylene glycol dimethyl acrylate
J. Braz. Chem. Soc.. Publicado em: 2018-01
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6. Hydrocortisone release from tablets based on bioresorbable poly(ether-ester-urethane)s
Abstract Bioresorbable linear poly(ether-ester-urethane)s with different hydrophilic characteristics were synthesized from triblock copolymers of poly(ε-caprolactone)-poly(ethylene oxide)-poly(ε-caprolactone) (PCL-PEO) as macrodiols, and L-lysine diisocyanate (LDI) or hexamethylenediisocyanate (HDI) were used as the required diisocyanates. Macrodiols were
Braz. J. Pharm. Sci.. Publicado em: 20/04/2017
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7. Design of a New Molecularly Imprinted Polymer Selective for Hydrochlorothiazide Based on Theoretical Predictions Using Gibbs Free Energy
A molecularly imprinted polymer (MIP) for the diuretic drug hydrochlorothiazide (HCTZ) based on theoretical predictions was developed. Molecular modeling calculations were performed to study the intermolecular interactions in the pre-polymerization mixture and to select a suitable functional monomer and a porogenic solvent for the synthesis of the MIP. To co
J. Braz. Chem. Soc.. Publicado em: 2016-12
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8. A New Post-Metallocene-Ti Catalyst with Maltolate Bidentade Ligand: an Investigation in Heterogeneous Polymerization Reactions in Different Mesoporous Supports
A new titanium catalyst easily synthesized from ethylmaltol bidentate chelator ligand was studied in homogeneous and heterogeneous ethylene polymerization. The dichlorobis(3-hydroxy-2-ethyl-4-pyrone)titanium(IV) complex was characterized by 1H and 13C NMR (nuclear magnetic resonance), UV-Vis and elemental analysis. Theoretical study by density functional the
J. Braz. Chem. Soc.. Publicado em: 2016-11
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9. Synthesis, Swelling Properties and Evaluation of Genotoxicity of Hydrogels Based on (Meth)acrylates and Itaconic Acid
In this study we prepared hydrogels based on 2-hydroxyethyl methacrylate (HEMA): PHEMA homopolymer and two terpolymers of HEMA, itaconic acid (IA) and two poly(alkylene glycol) (meth) acrylates (PAGM): poly(ethylene glycol)6 acrylate (P(HEMA/IA/PAGM1)) and poly(propylene glycol)5 methacrylate (P(HEMA/IA/PAGM2)). Hydrogels were synthesized by gamma-irradiated
Mat. Res.. Publicado em: 15/08/2016
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10. Polyethylene-polyaniline Nanofiber Composites: Evaluation of Experimental Conditions of in situ Polymerization
The difficult processability of polyaniline (PAni) can be overcome by preparing composites with high density polyethylene (HDPE), resulting in a conducting material with improved mechanical properties. PAni nanofibers were synthesized in this research using a rapid mixing method, while HDPE/PAni composites were prepared by in situ polymerization using Cp2ZrC
Mat. Res.. Publicado em: 23/10/2015
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11. Polymerization of Ethylene with Zirconocene Heterogenized on Spherical ZSM-5
Homogeneous polymerization catalysts require large amounts of solvent and cannot control the polymer morphology. In order to solve this issue, a narrow-shaped spherical ZSM-5 zeolite was used in ethylene polymerization as a support for zirconocene (Cp2ZrCl2). Several heterogeneous catalytic precursors were prepared and used in ethyle
J. Braz. Chem. Soc.. Publicado em: 2015-07
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12. Selective Determination of 2,4,6-Trinitrotoluene in Water Samples Based on Magnetic Imprinted Nanoparticles via Grafting Polymerization
The magnetic surface imprinted polymer was effectively synthesized based on grafting polymerization for selective determination of 2,4,6-trinitrotoluene (TNT) as template molecule. The "grafting to" procedure was performed by copolymerizing of vinyl modified magnetic substrate with methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) as function
J. Braz. Chem. Soc.. Publicado em: 2015-04