Branched Polymers
Mostrando 1-12 de 27 artigos, teses e dissertações.
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1. Application of Glycerol in the Synthesis of Hyperbranched and Highly Branched Polyethers: Characterization, Morphology and Mechanism Proposal
Hyperbranched biopolymers is an important class of polymer that is used in different areas, mainly in biomedicine. AB2 monomers are crucial to the development of a "hyperbranched" architecture of polyglycerol, being glycidol the most commonly used, even considering its environmental hazard. Glycerol carbonate is an ecologically accepted monomer synthesized d
Mat. Res.. Publicado em: 24/10/2019
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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. Polyol-polyesther matrices containing phthalocyanine derivatives macrocilces / Derivados de ftalocianina em sistemas poliméricos poliéster-poliol
Phthalocyanines are planar macrocycles with the presence of a central metal ion, formed by bridges of nitrogen and substituent groups in the aromatic rings adjacents. A large number of (PI) electrons, molecular symmetry and the possibility to coordinate different metals in nitrogen central atoms allows the use of these compounds in optical devices, light emi
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 06/05/2010
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4. Investigação da polimerização via radical livre usando iniciadores trifuncionais / Investigation of free radical polymerization using trifunctional initiators
Researchers from industries and universities have investigated the use of initiators with functionality greater than one, in free radical polymerization. These types of initiators are able to increase the polymerization reaction rate with no decrease in molecular weight. Besides, initiators with functionality greater than two (multifunctional initiators), th
Publicado em: 2009
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5. Modificações da parede celular de frutos do mamoeiro (Carica papaya L.) em diferentes estadios do desenvolvimento / Modifications of the cell wall of fruits of papaya (Carica papaya L.) at various stages of development
The plant cell wall is a unique component of plant tissues and its polysaccharide composition essential to understand food texture and its changes during post-harvestingl especially of climateric fruits, as is the case of papaya. The plant cell wall is composed of three domains: the first is formed by cellulose and hemicelluloses, the second of pectins and t
Publicado em: 2009
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6. Análise termodinâmica das reformas do metano (oxidativa e autotérmica), do etanol e da nafta
Catalytic reforming of hydrocarbons or other organic species is a technology usually employed in either improving traditional energy sources or producing alternative energy sources. Amongst the technologies employed in improving traditional energy sources, one can include catalytic reforming of petrochemical naphtha. Although being also employed to produce h
Publicado em: 2009
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7. Estudo do equilibrio de fases e de estruturas de complexos formados entre polietilenoiminas e dodecilsulfato / Phase equilibria and structural study of polyethyilenoimine and dodecylsulfate complexes
Polyelectrolytes associate strongly with oppositely charged surfactants in water, being able to generate liquid crystalline phases with interesting supramolecular structures. The geometry of the liquid crystalline phase depends on parameters such as: concentration, surfactant/monomer ratio, polymer characteristics and presence of cosolvents. The objective of
Publicado em: 2007
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8. Experimental investigation of free polymerization using mono e functional initiators / Pesquisa experimental sobre a polimerização via radical livre com iniciadores mono e difuncional
Monofunctional initiators are extensively utilized in free radical polymerization. In order to increase productivity, higher temperature or higher initial initiator concentration are used, therefore polymers with lower molecular weights are obtained. Bifunctional initiators increase the polymerization rate without decreasing the average molecular weight and
Publicado em: 2006
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9. Endo-beta-mananase de endosperma de Sesbania virgata (Cv.) Pers : purificação, caracterização e importancia na germinação e desenvolvimento da plantula
Many plant seeds have an endosperm, a tissue specialised either as storage or mechanical constraint to embryo growth. In many legume species, endosperms contain galactomannan. This polyssacharide is composed of a main chain of 1,4-β-mannan branched with variable amounts of 1,6-ά-linked galactosyl residues. Three enzymes produced by an aleurone laye
Publicado em: 2003
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10. Polissilanos e polissilanos ramificados
The polysilynes (SiPh)m, the linear polysilane (SiPhMe)n and the branched polysilanes [(SiPh)m(SiPhMe)n], [(SiPh)m(SiMe2)n], [(SiEt)m(SiPh2)n] and [(Sic-hex)m(SiPh2)n], with m/n ranging from 0,50/0,50 to 1,0/0,0, were synthesized in good yields from the sodium/toluene reductive coupling of the appropriate organochlorosilanes. The materiais were characterized
Publicado em: 1998
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11. Processos de polimerização e transição de colapso em polímeros ramificados. / Polymerization processes and collapse transition of branched polymers.
The phase diagram and the tricritical point of a collapsing lattice animal are studied through an extended series expansion of the isothermal compressibility KT on a square lattice. As a function of the variables x (fugacity) and y = e1/T (T is the reduced temperature), this series KT is investigated using the partial differential approximants technique. The
Publicado em: 1997
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12. Branched co-polymers of histidine and lysine are efficient carriers of plasmids
We previously determined that a linear co-polymer of histidine and lysine (HK) in combination with liposomes enhanced the transfection efficiency of cationic liposomes. In the current study, we designed a series of HK polymers with increased branching and/or histidine/lysine ratio to determine if either variable affects transfection efficiency. In the p
Oxford University Press.