Ethylene Polymerization
Mostrando 13-24 de 60 artigos, teses e dissertações.
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13. Ethylene Polymerization by 2-Methyl-8-(benzimidazol)quinolyliron(II) Pre‑Catalyst: a DFT Understanding its Chain Propagation and Transfer
O mecanismo de polimerização do etileno com o pré-catalisador 2-metil-8-(benzimidazol) quinoliliron(II) foi investigado através da teoria de densidade funcional (DFT), ilustrando possíveis intermediários com configurações geométricas e de spin. De acordo com o grupo ligado ao núcleo ferro, metila ou etila, as barreiras de energia para a inserção
J. Braz. Chem. Soc.. Publicado em: 2014-12
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14. Synthesis and Characterization of a Cationic Cyclopentadienyl Nickel(II) Complex of Bis(mesityl-imino)acenaphthene and its Evaluation as a New Catalyst Precursor for Ethylene Polymerization
O complexo catiônico ciclopentadienílico de níquel(II) contendo o ligante bis(mesitilimino) acenafteno, de fórmula [Ni(η5-C5H5)(Mes-BIAN)]PF6 (Mes = mesitil = 2,4,6-Me3-C6H2; Mes‑BIAN = bis(mesitil-imino)acenafteno), foi sintetizado através de duas estratégias alternativas, tendo sido obtido com rendimentos moderado a quantitativo. Apesar de ser ele
J. Braz. Chem. Soc.. Publicado em: 2014-12
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15. Solid state polymerization of pet/pc extruded blend: effect of reaction temperature on thermal, morphological and viscosity properties
A systematic study of solid state polymerization (SSP), concerning the melt extruded blend of poly(ethylene terephthalate)/polycarbonate (catalyzed PET/PC, 80/20 wt %), as a function of temperature range (180-190°C) for a fixed time (6 h) is presented. The materials obtained were evaluated by differential scanning calorimetry (DSC), thermogravimetry/derivat
Polímeros. Publicado em: 2014-08
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16. Preparation of poly(urethane-urea) nanoparticles containing açaí oil by miniemulsion polymerization
Polyurethane nanoparticles (NPs) are promising candidates for the controlled and targeted delivery of therapeutics in a variety of biomedical applications. In this work, a report is made of NPs produced by miniemulsion polymerization with isophorone diisocyanate (IPDI) and castor oil, glycerol, and poly(ethylene glycol) (PEG) with molar masses 400 and 1000 a
Polímeros. Publicado em: 27/08/2013
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17. Process analysis and optimization mapping through design of experiments and its application to a polymerization process
The technique of experimental design is used on an ethylene polymerization process model in order to map the feasible optimal region as preliminary information for process optimization. Through the use of this statistical tool, together with a detailed deterministic model validated with industrial data, it is possible to identify the most relevant variables
Brazilian Journal of Chemical Engineering. Publicado em: 2011-03
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18. In situ synthesis of nanoclay filled polyethylene using polymer supported metallocene catalyst system
In situ ethylene polymerizations were performed using bis(cyclopentadiene)titanium dichloride supported on polyethersulfone as catalyst. The bis(cyclopentadiene)titanium dichloride supported on polyethersulfone catalyst activity estimated by ethylene polymerization was 360 kgPE/molTi/h. During polymerization the fillers used were montmorillionite nanoclays h
Química Nova. Publicado em: 2011
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19. Síntese e caracterização de terpolímeros anfifílicos constituídos de poli(etileno glicol), l-lactídeo e glicolídeo / Synthesis and characterization of amphiphilic terpolymers constituted of poly(ethylene glycol), l-lactide and glycolide
Neste trabalho foram sintetizados copolímeros bi (triblocos) e tricomponentes (penta blocos) constituídos de poli(etileno glicol) (PEG), l-lactídeo (3,6-Dimetil-1,4-dioxano-2,5-diona - LLA) e glicolídeo (1,4-dioxano-2,5-diona - GL). A síntese foi realizada pelo método de polimerização por abertura de anel (Ring-Opening Polymerization ¿ ROP) utilizan
Publicado em: 2011
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20. Parameter estimation for LLDPE gas-phase reactor models
Product development and advanced control applications require models with good predictive capability. However, in some cases it is not possible to obtain good quality phenomenological models due to the lack of data or the presence of important unmeasured effects. The use of empirical models requires less investment in modeling, but implies the need for large
Publicado em: 2011
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21. Blendas de poli(metacrilato de metila) e do elastômero saturado poli(acrilonitrila-g-(etileno-co-propileno-co-dieno-g-estireno) obitdas por polimerização in situ / Blends of poly(methyl methacrylate) and the saturated elastomer poly(acrylonitrile-g-(ethylene-co-propylene-co-diene)-g-styrene) prepared by in situ polymerization
In this work, blends of the poly(methyl methacrylate), PMMA, and the poly[acrylonitrile-g-(ethylene-co-propylene-co-diene)-g-styrene], AES, were prepared. AES is a complex mixture of poly(styrene-co-acrylonitrile), SAN, and poly(ethylene-copropylene-co-diene), EPDM, and the graft copolymer EPDM-g-SAN. Blends PMMA-AES were obtained by polymerization in situ,
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 22/03/2010
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22. Control of branch formation in ethylene polymerization by a [Ni(eta3-2-MeC3H4)(diimine)] PF6/DEAC catalyst system
A polimerização de etileno em presença do precursor catalítico [Ni(3-2-MeC3H4)- {ArN=C(H)C(H)=NAr}]PF6, Ar = 2,6-C6H3 iPr2/DEAC sob condições reacionais brandas (temperatura de reação entre -10 °C e 25 °C e pressão de etileno entre 109 e 1520 kPa) conduz à formação de polietileno ramificado de alto peso molecular. A taxa de ramificação foi
Publicado em: 2010
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23. Titanium and vanadium ethylene polymerization catalysts containing tris(pyrazolyl)borate ligand: Effects of polymerization parameters on activity and polymer properties
O comportamento nas reações de polimerização de etileno envolvendo uma série de complexos de titânio(IV) e vanádio(V), [Tp´MXCl2] (1, M= Ti, Tp´= TpMs*, X = Cl; 2, M = Ti, Tp´= TpMs, X = Cl; 3, M = V, Tp´= TpMs*, X = NtBu; 4, M = V, Tp´= TpMs*, X = NAr) (TpMs*= HB(3-mesitilapirazolil) 2(5-mesitila-pirazolyl)–, TpMs = HB(3-mesitial-pirazolil)3 �
Publicado em: 2010
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24. Dual catalyst system composed by nickel and vanadium complexes containing nitrogen ligands for ethylene polymerization
Blendas de polietileno ramificado/polietileno de alta densidade (BPE/HDPE) foram preparadas usando uma combinação de catalisadores [NiCl2(diimina-α)] (1) (diimina-α = 1,4-bis(2,6- diisopropilfenila)-acenafeteno) e [TpMs*VCl2(NtBu)] (2) (TpMs* = hidridobis(3-mesitilapirazol-1- il)(5-mesitilapirazol-1-il)). As reações de polimerização foram realizadas
Publicado em: 2010