Divinylbenzene
Mostrando 1-12 de 54 artigos, teses e dissertações.
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1. Method for Cleaning Back-Produced Water from Polymer Flooding Operations to Determine Polymer Molar Mass Using Size-Exclusion Chromatography
One of the methods used by the oil industry to increase production is to inject water, containing polymer, into the reservoir. The viscosity of the aqueous solution is primarily responsible for the efficiency of this method, and is achieved using polymers with high molar mass. However, polymer degradation can occur during pumping and fluid displacement in th
J. Braz. Chem. Soc.. Publicado em: 2020-12
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2. OTIMIZAÇÃO DO PROCESSO NÃO INVASIVO E NÃO DESTRUTIVO DE EXTRAÇÃO E ANÁLISE DE METABÓLITOS VOLÁTEIS DE MAMÃO PAPAIA POR SPME-GC-MS
The analysis of volatiles is an alternative in the routine of quality control of fruits, since the volatile metabolites can change in the presence of microorganisms. A well-established method for extracting volatiles is the solid phase microextraction (SPME). This work aims to define some parameters (fiber coating, conditioning time and fiber exposure time)
Quím. Nova. Publicado em: 2020-09
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3. Factorial design to obtain magnetized poly(ethyl acrylate-co-divinylbenzene)
Abstract Magnetized polymers are produced by incorporating magnetic particles in a polymeric matrix. This article describes the use of the suspension polymerization technique using ethyl acrylate and divinylbenzene as monomers, in the presence of heptane and/or toluene as diluent, initiated by free radicals. To produce the polymer, we first performed fractio
Polímeros. Publicado em: 04/07/2019
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4. SPME Fiber Evaluation for Volatile Organic Compounds Extraction from Acerola
Volatile organic compounds (VOCs) were isolated from acerola fruits (Malpighia emarginata D.C.), by means of different solid phase microextraction (SPME) fibers. For the extraction, the headspace SPME method was used, identifying the VOCs by gas chromatography (GC) with mass spectrometry (MS). The objective of this work was to evaluate the efficiency of SPME
J. Braz. Chem. Soc.. Publicado em: 2019-02
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5. Evaluation of the Influence of Extraction Conditions on the Isolation and Identification of Volatile Compounds from Cagaita (Eugenia dysenterica) Using HS-SPME/GC-MS
The objective of this study was to explore the extraction and identification of volatile organic compounds (VOCs) present in cagaita fruit (Eugenia dysenterica). Parameters such as type of extraction fiber, agitation, extraction time and extraction temperature were investigated. Initially, the VOCs were extracted using headspace solid-phase microextraction.
J. Braz. Chem. Soc.. Publicado em: 2019-02
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6. ARTIFACTS IN THE ANALYSIS AND ASSESSMENT OF LOW-COST CONTAINERS FOR SAMPLING AND STORING GREENHOUSE GASES
The objectives of this study were twofold: to assess two chromatographic methods for the analysis of greenhouse gases (GHG) and carbon monoxide, and to propose and evaluate a low-cost and reusable alternative system for their sampling and storage, using 10 different container configurations (flasks and bags). To that end, standard samples containing the gase
Quím. Nova. Publicado em: 2019-01
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7. Influence of the Fraction of Comonomers and Diluents on the Preparation of Polymeric Microspheres Based on Poly (Methacrylic acid-co-divinylbenzene) Obtained by Precipitation Polymerization
Abstract Preparation and characterization of polymeric microspheres based on poly(methacrylic acid-co-divinylbenzene) (P(MAA-co-DVB)) by precipitation polymerization are reported. The influence of the change in comonomer composition, crosslinking degree, ratio of total monomers/diluents by weight/volume (g/100 mL) and the volume ratio of diluents were studie
Mat. Res.. Publicado em: 20/12/2018
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8. Kinetic Investigation of Thermal Formation Processes of SiOC Glasses Derived from C-Containing Hybrid Polymeric Networks
In this study, hybrid polymeric networks were prepared by hydrosilylation reaction as precursors to silicon oxycarbide (SiOC) glass. The polymeric networks were prepared from poly(methylsiloxane) (PMS) and divinylbenzene (DVB) in the 80:20 and 20:80 (PMS/DVB) compositions, with or without activated charcoal (AC), which was used as additional carbon source. F
J. Braz. Chem. Soc.. Publicado em: 2015-05
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9. HS-SPME-GC-MS ANALYSIS OF VOLATILE AND SEMI-VOLATILE COMPOUNDS FROM DRIED LEAVES OF Mikania glomerata Sprengel
This paper reports on the identification of volatile and semi-volatile compounds and a comparison of the chromatographic profiles obtained by Headspace Solid-Phase Microextraction/Gas Chromatography with Mass Spectrometry detection (HS-SPME-GC-MS) of dried leaves of Mikania glomerata Sprengel (Asteraceae), also known as 'guaco.' Three different types of comm
Quím. Nova. Publicado em: 2015-03
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10. Removal of Phenol from aqueous solutions by Polymeric composites containing Ni and Co particles
Magnetic composites have a wide range of potential technological applications; however the evaluation of this material for extraction of phenolic compounds has not been sufficiently studied. Due to its high toxicity and solubility the removal of phenolic compounds from the aquatic environments has critical importance. In this work polymeric composites were p
Polímeros. Publicado em: 25/10/2013
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11. Sorption of 2-Chlorophenol from aqueous solutions by functionalized cross-linked polymers
This manuscript describes the synthesis of three polymers based on styrene (STY), divinylbenzene (DVB) and two different vinyl monomers: methyl methacrylate (MMA) and acrylonitrile (AN). The STY-DVB, STY-DVB-MMA and STY-DVB-AN polymers were synthesized employing the aqueous suspension technique. Reaction yields were 73%, 81% and 75%, respectively. They were
Polímeros. Publicado em: 2013
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12. Desenvolvimento e aplicação de técnicas miniaturizadas de preparo de amostra na determinação de fármacos no ambiente / Development and application of microextraction sample preparation techniques to determine pharmaceutical drugs in the environment
The occurrence of pharmaceutical drugs in the environment is a worldwide problem caused by the genotoxicity and ecotoxicity activities of those compounds. Water is one of most used natural resource in human activities which explain the presence of emerging contaminants. Those compounds affect not only humans but also aquatic animals that spend the whole life
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 10/08/2012