Polysiloxanes
Mostrando 1-12 de 12 artigos, teses e dissertações.
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1. Ibuprofen, Carbamazepine and β-Estradiol Determination Using Thin-Film Microextraction and Gas Chromatography-Mass Spectrometry
The use of thin-film microextraction for the extraction of selected pharmaceutical compounds followed by gas chromatography-mass spectrometry detection was evaluated. A segment of polysiloxanes polymer sheet was used as low cost, single use, disposable extraction phase, while Milli-Q water spiked at 20 µg L−1 with the analytes was used for the optimizatio
J. Braz. Chem. Soc.. Publicado em: 2016-10
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2. VIDROS DE OXICARBETO DE SILÍCIO OBTIDOS A PARTIR DE POLISSILOXANOS
AbstractSilicon oxycarbide glasses (SiOC) are a class of amorphous materials with a similar silica glass structure, in which oxygen atoms are partially replaced by tetracoordenated carbon atoms. The presence of carbon atoms covalently bound to the silicon atoms creates a more interconnected structure with better strength, and excellent chemical stability tha
Quím. Nova. Publicado em: 2015-08
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3. Aplicação de polissiloxanos imobilizados sobre sílica como fase estacionária e como sorvente na determinação de agrotóxicos em água e caldo de cana / Application of polysiloxanes immobilized on silica as stationary phases and as sorbents in the determination of agrotoxics in water and sugar cane juice
Neste trabalho verificou-se a potencialidade de uso de sorventes e fases estacionárias (FE), obtidos a partir da sorção e/ou imobilização do polímero poli(metiloctilsiloxano) (PMOS) sobre suportes de sílica Kromasil utilizando tamento térmico, na separação, quantificação e validação de uma metodologia para análise de agrotóxicos em amostras d
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 02/06/2010
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4. Determinação da espessura da camada polimérica de fases estacionárias imobilizadas para cromatografia líquida de alta eficiência por termogravimetria
This paper presents a simple and practical thermogravimetric method for determining the layer thickness of immobilized polymer stationary phases used in reversed-phase high-performance liquid chromatography. In this method, the weight loss of different polysiloxanes immobilized onto chromatographic supports, determined over the temperature range 150-650 ºC,
Química Nova. Publicado em: 2008
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5. Modificações induzidas por ions de alta energia em filmes finos de organosilicones sintetizados por PECVD / Modifications induced by high energy ions in organosilicones thin films syntesized by PECVD
Thin films of polysiloxanes, polysilazanes and polycarbosilanes, synthesized by Plasma Enhanced Chemical Vapor Deposition (PECVD), were irradiated with 170 keV He + , Ne + , Ar + and Kr + ions, at 170 keV at fluences of 1x10 14 , 5 x10 14 , 1x10 15 , 5x10 15 and 1 x10 16 ions/cm -2 . The irradiation promoted significant modifications in the atomic compositio
Publicado em: 2007
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6. Modifications induced by high energy ions in organosilicones thin films syntesized by PECVD / Modificações induzidas por ions de alta energia em filmes finos de organosilicones sintetizados por PECVD
Thin films of polysiloxanes, polysilazanes and polycarbosilanes, synthesized by Plasma Enhanced Chemical Vapor Deposition (PECVD), were irradiated with 170 keV He + , Ne + , Ar + and Kr + ions, at 170 keV at fluences of 1x10 14 , 5 x10 14 , 1x10 15 , 5x10 15 and 1 x10 16 ions/cm -2 . The irradiation promoted significant modifications in the atomic compositio
Publicado em: 2007
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7. Sinterização de matrizes cerâmicas à base de alumina reforçadas por carbetos a partir de precursores poliméricos
Ceramic composites produced with polymerics precursors have been studied for many years, due to the facility of obtaining a complex shape, at low temperature and reduces cost. The main objective of this work is to study the process of sintering of composites of ceramic base consisting of Al2O3 and silicates, reinforced for NbC, through the technique of proce
Publicado em: 2007
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8. Silicone resin to improve corrosion resistance of Zn and ZnFe coated steel
Chromatation pre-treatments have been widely used to improve galvanized steel corrosion resistance. However, due to the high toxicity of chromate ions, chromatation pre-treatments tend to be banned and, in last years, alternative coating systems are under investigation. Recently, polysiloxanes have been developed for application as coatings. Among them, and
Matéria (Rio J.). Publicado em: 2006
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9. Cellulose acetate and polysiloxane hybrids, preparation, properties and morphology / Hibridos de acetato de celulose e polissiloxanos : preparação, propriedades e morfologia
O tema central deste trabalho foi a preparação, a caracterização morfológica e a avaliação das propriedades físicas de híbridos de acetato de celulose e polissiloxanos utilizando o processo sol-gel. Inicialmente, foram sintetizadas unidades funcionais a partir da reação dos monômeros orgânicos pentaeritritoltriacrilato (PETA) ou trisisocianurato
Publicado em: 2005
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10. Preparação de colunas para cromatografia liquida de alta eficiencia recheadas com polissiloxanos (C1, C8 e C14) imobilizados sobre particulas de silica porosa de 5mum
In this work, reversed phases for High-Performance Liquid Chromatography (HPLC) were obtained by deposition of polysiloxanes with different lateral chains, C1 (polydimethylsiloxane), C8 (polymethyloctylsiloxane) and C14 (polymethyltetradecylsiloxane), in HPLC silica particles, followed by immobilizatíon using different processes: thermal treatment, self-imm
Publicado em: 2004
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11. Determinação multirresiduos de pesticidas em agua por cromatografia liquida de alta eficiencia com enfase em detecção por espectrometria de massas e novos sorventes para extração em fase solida
A multiresidue method for determination of pesticides in water samples was developed. The following pesticides were studied: 2,4-D, linuron, diuron, atrazine, ametryn, tebuthiuron, simazine, dimethoate, carbendazim, carbaryl and 3,4-DCA. Two methods of extraction and preconcentration were compared: liquid-liquid extraction (LLE) and solid-phase extraction (S
Publicado em: 2001
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12. Reações interfaciais de Poli(dimetilsiloxano)s com superficies hidroxiladas
Polysiloxanes, commonly know as silicones, are polymers formed by an Si-O backbone containing organic groups attached to the silicon atoms. Their chemistry is basically determined by the polarization of the Si-O bonds, and by the structure of the pendant organic groups. The Si-O bond is highly resistant to homolytic cleavage, but is susceptible to heterolyti
Publicado em: 1997