Polymerization
Mostrando 1-12 de 1992 artigos, teses e dissertações.
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1. Characterization and mechanical properties of one-part geopolymer based on a pure metakaolin
Abstract Geopolymers are amorphous silicate polymers that have been extensively studied due to their applications, scientific and technical relevance, and their potential as cement in substitution to Portland. Much of the focus has been in the use of precursors and aggregates that are rarely pure and homogeneous with the use of tailings being very common. Th
REM - International Engineering Journal. Publicado em: 2022
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2. Effect of a polymerization inhibitor on the chemomechanical properties and consistency of experimental resin composites
Resumo O objetivo foi investigar o efeito do inibidor de polimerização BHT no grau de conversão (GC), resistência à flexão (RF), módulo de flexão (MF), microdureza Knoop (KH) e redução da microdureza (RKH), e consistência de um compósito experimental contendo diferentes concentrações de BHT (% em peso): C0 - controle (0%); C0,01 (0,01%); C0,025
Brazilian Dental Journal. Publicado em: 2022
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3. Porosity of CHA Zeolite Driving the Formation of Polyaromatic Coke Species in the Methanol to Olefins Reaction
The pore size of the chabazite structure is exceptionally suitable for the methanol to olefins (MTO) reaction. The reaction has an induction period required for the formation of a hydrocarbon pool (HP), usually composed of aromatic compounds of different sizes. HP is alkylated by methanol and afterward cracked, leading to the formation of olefins. Despite th
J. Braz. Chem. Soc.. Publicado em: 2021-05
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4. POLÍMERO DE IMPRESSÃO MOLECULAR PARA O TIACLOPRIDO: UMA INVESTIGAÇÃO TEÓRICA
Thiacloprid (TCP) is a synthetic insecticide, belonging to the class of neonicotinoids (NNCs), which present potential damages to the environment, biodiversity and human health, being necessary its constant monitoring. In this sense, molecularly imprinted polymers (MIPs) have been shown as an excellent alternative for the separation science, since they can r
Quím. Nova. Publicado em: 2020-12
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5. Gelation of commercial pea protein isolate: effect of microbial transglutaminase and thermal processing
Abstract In the studied commercial pea protein isolate (PPI) some physicochemical modifications are induced in the protein structure during its processing. That fact would result into a reduction of proteins techno-functional properties. It has been evidenced by Differential Scanning Calorimetry the protein denaturation what gives as a result poor gelling ab
Food Sci. Technol. Publicado em: 2020-12
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6. Exploring Polypyrrole as Extraction Phase for Disposable Pipette Extraction Method for Multiclass Organic Micro-Pollutant Determination in River and Tap Water Using Gas Chromatography-Mass Spectrometry
The use of a polypyrrole (PPy) is described as an efficient extraction phase for disposable pipette extraction (DPX), in a fast and ruggedized analytical method for simultaneous determination of 18 organic micro-pollutants in water using gas chromatography-mass spectrometry (GC-MS). The DPX-blank pipettes were filled with PPy, a material produced through the
J. Braz. Chem. Soc.. Publicado em: 2020-10
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7. Effects of Temperature and Concentration on the Determination of PET Viscosity
This work describes the use of experiment planning to investigate the effects of the variables temperature and concentration of the polymer solution on the viscosity test of polyethylene terephthalate (PET). For this, the response surface methodology was based on a central composite rotatable design (CCRD) to optimize the combinations of the analytical condi
J. Braz. Chem. Soc.. Publicado em: 2020-09
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8. 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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9. Rapid Determination of Vitamins D2 and D3 in Dairy Products by High-Performance Liquid Chromatography after Solid Phase Extraction Based on Polystyrene/Polypyrrole Composite Nanofibers
The detection of vitamin D in complex samples is challenging because of the instability of vitamin D in sample preparation. To resolve this problem, packed-fiber solid-phase extraction (PFSPE) has been successfully developed for the pre-treatment of samples containing vitamin D2 (D2) and vitamin D3 (D3) in dairy products. Based on PFSPE, vitamin D could avoi
J. Braz. Chem. Soc.. Publicado em: 2020-06
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10. 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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11. CONSTRUÇÃO DE MINI FORNO PARA FUNCIONALIZAÇÃO TÉRMICA DE FASES ESTACIONÁRIAS MONOLÍTICAS
The present work describes a mini oven built to be applied in the preparation of monolithic stationary phase through the thermal polymerization approach. The developed device was successfully tested for functionalization of monolithic stationary phase in the internal surface of the silica capillary column fused with gold nanoparticles.
Quím. Nova. Publicado em: 2020-03
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12. PMMA-SiO2 Organic-Inorganic Hybrid Coating Application to Ti-6Al-4V Alloy Prepared through the Sol-Gel Method
Siloxane-poly(methyl methacrylate) (PMMA) hybrid was synthesized based on the sol-gel method and applied to Ti-6Al-4V through dip-coating. The structural feature of the hybrid was subjected to Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TG); its morphological properties were analyzed through scanning electron microscope (SE
J. Braz. Chem. Soc.. Publicado em: 2020-02