Oligomers
Mostrando 1-12 de 1167 artigos, teses e dissertações.
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1. SPECTROSCOPIC CHARACTERIZATION OF PEDOT:PSS CONDUCTING POLYMER BY RESONANCE RAMAN AND SERRS SPECTROSCOPIES
Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) synthesis was monitored by resonance Raman (RR) and surface-enhanced resonance Raman scattering (SERRS) spectroscopies and both the oxidation of the polymer and the effects of chain length were assessed by vibrational analysis. It was supported by theoretical models of oligomers, with charge
Quím. Nova. Publicado em: 05/12/2019
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2. Gold Nanoparticles and [PEDOT-Poly(D,L-Lactic Acid)] Composite: Synthesis, Characterization and Application to H2O2 Sensing
Biocompatible electrochemical devices are challenging to develop due to the toxicity of many advanced electrode materials and the difficulty to degrade the discarded material. Few recent advances were made in the synthesis of conducting biodegradable composites of polymers for electrode materials. In this article we describe the synthesis of two new inorgani
J. Braz. Chem. Soc.. Publicado em: 21/10/2019
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3. Synthesis and characterization of isoprene oligomers to compare different production chemical processes
Abstract Three methods to obtain isoprene oligomers were evaluated: chemical degradation of non-vulcanized coagulated natural rubber; chemical degradation of natural rubber latex; and oligomerization of the isoprene monomer. The products were characterized by infrared spectrometry (FTIR), nuclear magnetic resonance (NMR) and size-exclusion chromatography (S
Polímeros. Publicado em: 18/03/2019
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4. Effect of sawdust as porosity agent on final properties of geopolymers
Abstract The geopolymers synthesis are based on geopolymerization, a sequence of reactions processed in an alkaline medium through oligomers providing a three-dimensional molecular structure. In this work, the polycondensation of metakaolin was performed with alkaline activators (NaOH and sodium silicate), wood sawdust and other additives. Two different comp
Cerâmica. Publicado em: 2019-01
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5. Película biodegradable de almidón de maíz termoplástico y quitosano con actividad antimicrobiana empleada como envase activo
ABSTRACT One of the research lines related to active packaging takes into account the incorporation of antimicrobial agents such as chitosan, a polysaccharide derived from the crustaceans’ exoskeleton. However, because of chitosan high molar mass, its diffusion from the package to the food surface is restricted, so the use of oligomers is an interesting bu
Matéria (Rio J.). Publicado em: 19/07/2018
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6. Molecular dynamics studies of amylose plasticized with Brazilian Cerrado oils: part I
Abstract Biodegradable polymers have become part of the realm of polymer science with specially when associated to renewable sources. Unraveling the plasticizer effect of natural occurring fatty acids in the Brazilian Cerrado on amylose oligomers was aimed in this work in an aqueous environment. Since the interactions within a material are of extreme import
Polímeros. Publicado em: 28/06/2018
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7. The role of condensed tannins in ruminant animal production: advances, limitations and future directions
ABSTRACT Tannins represent one of the most abundant polyphenolic compounds in plants. Tannins exist as a multitude of chemically unique entities in nature. The most commonly occurring tannins are typically divided into two major classes based on chemical structure: hydrolysable (HT) or condensed tannins (CT). Hydrolysable tannins are esters of gallic or ella
R. Bras. Zootec.. Publicado em: 2017-12
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8. Unraveling the Role of Π - Conjugation in Thiophene Oligomers for Optoelectronic Properties by DFT/TDDFT Approach
ABSTRACT Thiophene oligomer has been investigated using DFT/TDDFT calculations with an aim to check its suitability for opto electronic applications and also to analyse the influence of π-bridge. Our results revealed that thiophene oligomers have excellent π-conjugation throughout. FMO analysis give an estimate of band gap of thiophene oligomer and further
Braz. arch. biol. technol.. Publicado em: 23/01/2017
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9. Hybrid Nanocomposites Based on Epoxy/silsesquioxanes Matrices Reinforced with Multi-walled Carbon Nanotubes
The aim of this work was the synthesis of hybrid organic-inorganic epoxy-copolysilsesquioxane nanocomposites reinforced with multi-walled carbon nanotubes (MWCNT). Copolysilsesquioxanes oligomers from 3-aminopropyltriethoxysilane (APTES) and phenyltriethoxysilane (PTES) precursors have been synthesized by a sol-gel process and chemically incorporated to an e
Mat. Res.. Publicado em: 24/11/2015
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10. Electrosynthesis and Characterisation of Polymer Nanowires from Thiophene and its Oligomers
Validating methodology formerly reported, polythiophene electrosynthesised as nanowires from the monomer and some of its oligomers is now described. The work is conducted on a platinum electrode previously modified with a template that tunes the polymer growth inside the confined space of the pores. In addition, it was confirmed that the use of larger chain-
J. Braz. Chem. Soc.. Publicado em: 2015-11
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11. A THEORETICAL EVALUATION OF ELECTROCONDUCTIVE PROPERTIES FOR [1,2,4]-TRIAZOLE 4N-SUBSTITUTED POLYMERS
In order to evaluate a set of electrical and optical properties by using time-dependent density functional theory (TD-DFT), at level of theory B3LYP/6-31G(d), the 4N-substituted [1,2,4]-Triazole (TAZ) oligomers and substituted derivatives were studied using cyano, amino, methyl and fluoro functional groups. Additionally, specific properties were theoretic
Quím. Nova. Publicado em: 2015-06
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12. The use of lysozyme to prepare biologically active chitooligomers
Two types of crustacean commercial chitosans (CS1, CS2) were dissolved in lactic acid solutions, hydrolysed by lysozyme and finally fractioned by methanol solutions into two parts containing chito-oligomers (CS-O1, CS-O2). The antioxidant power and antimicrobial properties of both fractions were studied and compared with non-hydrolysed CS1 and CS2. The antio
Polímeros. Publicado em: 2015-02