Precursors Polymers
Mostrando 1-12 de 25 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. Synthesis of Submicrometer Calcium Carbonate Particles from Inorganic Salts Using Linear Polymers as Crystallization Modifiers
In this study, we report the synthesis of submicrometer calcium carbonate particles using the simplest approach of mixing solutions of calcium chloride and ammonium carbonate inorganic precursors in the presence of crystallization modifiers. Instead of the typical crystallization of CaCO3 into large calcite crystals with rhombohedral morphology, very small u
J. Braz. Chem. Soc.. Publicado em: 2017-04
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3. New Flexible and Transparent Solution-Based Germanium-Sulfide Polymeric Materials
New flexible and transparent materials based on germanium sulfide were obtained using GeCl4 and 1,3-propanedithiol as precursors. These materials have transparency in the ultraviolet-visible (UV-Vis) spectral region (about 70%), thermal stability up to 200 °C and glass transition located at temperatures below 0 °C (-37 °C, -56 °C and -59 °C) as shown by
J. Braz. Chem. Soc.. Publicado em: 2015-05
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4. Mangiferin: microencapsulation in pectin/chitosan systems, in vitro intestinal metabolism and anticancer activity. / MANGIFERINA: MICROENCAPSULAMENTO EM SISTEMAS PECTINA/QUITOSANA, METABOLISMO INTESTINAL IN VITRO E ATIVIDADE ANTICANCER
MANGIFERIN: MICROENCAPSULATION IN PECTIN/CHITOSAN SYSTEMS, IN VITRO INTESTINAL METABOLISM AND ANTICANCER ACTIVITY This work was performed in four parts: The first part refers to the isolation of pectin from a regional pumpkin in order to be used as matrix for drug encapsulation: Pumpkin (Cucurbita moschata) is an excellent and low cost source of carotenoids,
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 28/08/2012
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5. Sulfonation and characterization of styrene-indene copolymers for the development of proton conducting polymer membranes
The aim of this work is to obtain polymer precursors based on styrene copolymers with distinct degrees of sulfonation, as an alternative material for fuel cell membranes. Acetyl sulfate was used to carry out the sulfonation and the performance of the polyelectrolyte was evaluated based on the content of acid polar groups incorporated into the macromolecular
Polímeros. Publicado em: 30/10/2012
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6. New PHA products using unrelated carbon sources
Polyhydroxyalkanoates (PHA) are natural polyesters stored by a wide range of bacteria as carbon source reserve. Due to its chemical characteristics and biodegradability PHA can be used in chemical, medical and pharmaceutical industry for many human purposes. Over the past years, few Burkholderia species have become known for production of PHA. Aside from tha
Braz. J. Microbiol.. Publicado em: 2011-12
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7. Compósitos de matriz cerâmica contendo cargas com diferentes condutividades elétricas / Ceramic matrix composites containing fillers with different electrical conductivities
Neste trabalho pretendeu-se obter compósitos de matriz cerâmica à base de oxicarbeto de silício, SiCxOy, carregados com cargas de diferentes naturezas (grafite (GCM), carbeto de silício (SCM) e siliceto de tungstênio (WCM)), de modo a explorar a influência destas cargas na condutividade das vitrocerâmicas obtidas. Os CMC foram preparados pela piróli
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 16/03/2010
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8. Estudo comparativo de colágeno hidrolisado e comercial com adição de PVA / Comparative study of commercial and anionic collagen blended with PVA
The development of new materials has been based on the mix of two or more polymers or biopolymers where solutions are mixed in different portions trying to get materials with distinct properties from their precursors. In this work different collagen solutions and collagen-PVA blends were analyzed. The used collagen was the type I, however obtained from two d
Publicado em: 2009
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9. Preparation and reative studies of catalytic systems based on zirconocenes, face to homo-and co-polimerization reation of etene / Preparação e estudo de reatividade de sistemas catalíticos, a base de zirconocenos, frente à reação de homo- e copolimerização de eteno
Catalytic systems based on zirconoces which are able to polymerize ethene have been studied. Structural modifications on the basic catalytic precursor, diphenylmethylidene(η5- cyclopentadienyl)(η5-9-fluorenyl) zirconium dichloride (5a) have been carried out. The catalytic precursors 5a and bis(para-fluorophenyl)methylidene(η5-cyclopentadienyl)
Publicado em: 2007
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10. Early and post transition metal complexes as a single of combined components in the ethylene and isoprene polynerization
In this work is reported, in a first step, the effect of different experimental parameters and their relation with polymer properties using the homogeneous binary catalyst system composed by Ni(α-diimine)Cl2 (α-diimine = 1,4-bis(2,6-diisopropylphenyl)- acenaphthenediimine) and {TpMs*}V(Ntbu)Cl2 (TpMs* = hydridobis(3-mesitylpyrazol-1- yl)(5-mesitylpyrazol-1
Publicado em: 2007
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11. Evaluation of the chemical composition of the cell wall of transgenic tobacco plants (Nicotiana tabacum) that superexpress the gene ugdh, that codes for the enzyme UDPglucose dehydrogenase (EC 1.1.1.22) / Avaliação da composição química da parede celular de plantas de tabaco (Nicotiana tabacum) que superexpressam o gene ugdh de soja, que codifica a enzima UDP-glicose desidrogenase (EC 1.1.1.22)
The cellular elements that constitute the xylematic tissue of various plant species are widely used in diverse industrial sectors, with numerous applications, for example, the generation of energy and production of cellulose and paper. Plant cell walls are basically formed by cellulose, hemicellulose and lignin. The formation of cellulose and hemicellulose p
Publicado em: 2007
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12. Synthesis and characterization of Rare Earth compounds with potencial appplication in ionizing radiation detection / Síntese e caracterização de compostos de terras raras com potencial aplicação na detecção de radiação ionizante
Rare Earth (RE) inorganic phosphors play an important role as ionizing radiation detectors when applied to medical imaging techniques like radiology and tomography. These phosphors is to convert the high energy radiation absorbed photons (X or ?-rays) into visible photons, leading to better quality images and reducing the time the patient is exposed to radia
Publicado em: 2006