Polyethylenes
Mostrando 1-11 de 11 artigos, teses e dissertações.
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1. Predicting LDPE/HDPE blend composition by CARS-PLS regression and confocal Raman spectroscopy
Abstract Industries and the scientific community currently focus on creating new ways to recycle and to reuse polymer waste that leads to serious socio-environmental risks. However, the quality of recycled polyethylenes depends strongly on their purity degree, but the distinction between Low Density Polyethylene (LDPE) and High Density Polyethylene (HDPE) b
Polímeros. Publicado em: 18/03/2019
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2. 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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3. 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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4. Estudo da caracterização de espumas de polietileno reticulado pelo processo de irradiação com feixe de elétrons / Study of the caracterization of crosslinking polyethylene foam by irradiation process with electron beam
As espumas de polietileno são amplamente utilizadas. Suas aplicações vão de aparelhos domésticos a artefatos médicos, incluindo aplicações nas indústrias de construção civil e automobilística. As propriedades das espumas dependem da densidade e da sua estrutura celular, em outras palavras, da quantidade de células abertas e fechadas, da distribu
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 28/02/2007
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5. Desenvolvimento de um modelo para projeções de preços de polietilenos no mercado petroquímico brasileiro
O presente estudo propõe um modelo de projeção de preços de curto-prazo para os polietilenos no mercado petroquímico brasileiro. O modelo foi desenvolvido através de testes com o uso das técnicas de regressão múltipla e de redes neurais artificiais (RNA) como instrumentos de previsão, comparando-se os resultados das mesmas. A seleção das variáve
Publicado em: 2007
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6. Novel catalyst systems based on Ni(II), Ti(IV), and Cr(III) complexes for oligo-and polymerization of ethylene
The complex of Brookhart Ni(α-diimine)Cl2 (1) (α-diimine = 1,4-bis(2,6- diisopropylphenyl)-acenaphthenediimine) has been characterized after impregnation on silica (S1) and MAO-modified silicas (4.0, 8.0 and 23.0 wts.% Al/SiO2 called S2, S3 and S4, respectively). The treatment of these heterogeneous systems with MAO produces some active catalysts for the p
Publicado em: 2007
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7. Avaliação do desempenho de embalagens para alimentos quando submetidas a tratamento por radiação ionizante / Evaluation of performance of food packagings when treated with ionizing radiation
In this study the mechanical properties (tensile strength and percentage elongation at break and penetration resistance), optical properties, gas oxygen and water vapor permeability, the overall migration tests into aqueous food simulant (3% aqueous acetic acid) and fatty food simulant (n-heptane), as well as the formation of volatile radiation product tests
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 07/03/2006
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8. Photophysical properties of polymers modified with light-emitting groups : crosslinked polyethylenes and poly (methyl methacrylate) / Propriedades fotofisicas de polimeros modificados com grupos emissores : polietilenos reticulados e poli (metacrilato de metila)
Fluorescent systems with interesting photophysical properties were the aim of this work. Fluorescent molecules sorbed into polymeric matrices can act as local probes for any mechanical processes that occur leading to changes in the optical response of the probe. In this work pyrene and a carbazole derivative were employed as fluorescent sensor for relaxation
Publicado em: 2006
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9. Lungs mechanisms and pulmonary function evaluation after polyethyleneglycol addition to the exogenous surfactant in an experimental model of ARDS / "Avaliação dos efeitos da adição do polietilenoglicol ao surfactante pulmonar exógeno na função pulmonar, em um modelo experimental de síndrome de desconforto respiratório tipo agudo"
O surfactante pulmonar é uma substância fundamental na mecânica pulmonar, com atividade biofísica e de proteção alveolar por reduzir a tensão superficial e impedir o seu colabamento.Na síndrome do desconforto respiratório tipo agudo(SDRA) ocorre uma diminuição quantitativa e disfunção qualitativa do surfactante com agravamento do quadro clínico
Publicado em: 2005
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10. Blendas de poli(metacrilato de metila) (PMMA) e polietileno linear de baixa densidade (PELBD)
The aim of this work was to study blends of poly(methyl methacrylate), PMMA, and three kinds of linear low density polyethylene, LLDPE, each having distinct microstructures. Their mechanical or morphological properties were determined in function of composition, processing conditions and route of compatibilization. Blends of PMMA/LLDPE were prepared in a con
Publicado em: 2001
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11. Biodegradation of Degradable Plastic Polyethylene by Phanerochaete and Streptomyces Species †
The ability of lignin-degrading microorganisms to attack degradable plastics was investigated in pure shake flask culture studies. The degradable plastic used in this study was produced commercially by using the Archer-Daniels-Midland POLYCLEAN masterbatch and contained pro-oxidant and 6% starch. The known lignin-degrading bacteria Streptomyces viridosporus