Sulfonation
Mostrando 1-12 de 26 artigos, teses e dissertações.
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1. MODIFICAÇÃO QUÍMICA DO POLIPROPILENO ATRAVÉS DA INTRODUÇÃO DE GRUPOS SULFÔNICOS PARA APLICAÇÃO COMO CATALISADOR EM REAÇÕES DE ESTERIFICAÇÃO
In this work, the chemical modification of pristine polypropylene was carried out through sulfonation reactions with concentrated sulfuric acid (PPS1) and fuming sulfuric acid (PPS2), for production of heterogeneous catalysts used in esterification reactions. Fourier transform infrared spectroscopy, elemental analysis, degree of substitution and ion exchange
Quím. Nova. Publicado em: 2021-04
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2. Adding value to polystyrene waste by chemically transforming it into sulfonated polystyrene
ABSTRACT Polystyrene (PS), one of the most used polymers in everyday life, has a low recycling rate due to its inexpensive virgin resin. In order to make polystyrene waste (WPS) recycling advantageous, it is possible to change it chemically, introducing heteroatoms in the polymer chain thus transforming the waste into a material with more added value. In thi
Matéria (Rio J.). Publicado em: 16/09/2019
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3. Sulfonated Styrene-Acrylic Acid Copolymers with pH-Indicator Property
In this study, a polymer pH-indicator was synthesized by sulfonation of poly(styrene-co-acrylic acid) with concentrated sulfuric acid. The synthesized polymer pH-indicator exhibited pH-responsive color changes in aqueous solutions, being purple in alkaline medium (pH < 4), whereas yellow in acidic medium (pH > 9). The sulfonation process extent and polymer c
J. Braz. Chem. Soc.. Publicado em: 16/09/2019
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4. Sulfonated poly(ether ether ketone)/hydroxyapatite membrane as biomaterials: process evaluation
Abstract Poly(ether ether ketone) (PEEK) has excellent properties, such as high biocompatibility and an elastic modulus similar to bone, which makes it a suitable biomaterial. When modified with sulfuric acid (H2SO4) and hydroxyapatite (HA), its workability and bioactivity is enhanced, and this makes it of great importance in medicine. This study investigat
Polímeros. Publicado em: 18/03/2019
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5. Nafion/sulfonated poly(indene) polyelectrolyte membranes for fuel cell application
Abstract Sulfonated poly(indene) (SPInd), with 35% and 45% degree of sulfonation, was blended with Nafion to prepare blended membranes with 10, 15 and 20 wt.% of SPInd. Membranes were evaluated by infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy and X-ray diffraction. Water uptake (WU), ion ex
Polímeros. Publicado em: 10/07/2018
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6. Proton Exchange Membrane Based on Sulfonated Poly (Aromatic Imide-Co-Aliphatic Imide) for Direct Methanol Fuel Cell
A new sulfonated poly(aromatic imide-co-aliphatic imide) (SPI) for the use as a polymer electrolyte membrane was successfully synthesized from 4,4'-diaminodiphenylmethane (DDM), 4,4'-diaminodiphenylmethane-2,2'-disulfonic acid disodium salt (S-DDM), hexamethylenediamine, and 3,3',4,4'-benzophenonetetracarboxylic dianhydride in a one-step reaction. S-DDM was
Mat. Res.. Publicado em: 18/12/2017
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7. Sulfonation degree effect on ion-conducting SPEEK-titanium oxide membranes properties
Abstract Polymeric membranes were developed using a SPEEK (sulfonated poly(ether ether ketone)) polymer matrix, containing titanium oxide (TiO2) (incorporated by sol-gel method). SPEEK with different sulfonation degrees (SD): 63% and 50% were used. The influence of sulfonation degree on membrane properties was investigated. The thermal analysis (TGA and DTGA
Polímeros. Publicado em: 21/09/2017
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8. Proton conductive membranes based on poly (styrene-co-allyl alcohol) semi-IPN
The optimization of fuel cell materials, particularly polymer membranes, for PEMFC has driven the development of methods and alternatives to achieve systems with more adequate properties to this application. The sulfonation of poly (styrene-co-allyl alcohol) (PSAA), using sulfonating agent:styrene ratios of 2:1, 1:1, 1:2, 1:4, 1:6, 1:8 and 1:10, was previous
Polímeros. Publicado em: 10/06/2014
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9. Synthesis and characterization of sulfonated poly(ether imide) with higher thermal stability and effect on CO2, N2, and O2 permeabilities
An experimental design in different reaction conditions was applied to modify poly(ether imide), PEI, by sulfonation using acetyl sulfate. Higher temperatures and reaction times led to higher ion exchange capacity. The thermal analysis showed that our sulfonation approach accomplished preparing sulfonated PEI maintaining the thermal stability of its parent m
Mat. Res.. Publicado em: 18/02/2014
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10. 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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11. Sulfonated polyaniline: influence of sulfonation routes on its thermal and structural characteristics
In order to study the influence of different sulfonation routes on its thermal and structural properties sulfonated polyaniline (SPAni) was prepared. FT-IR revealed that the formation of PAni salt or ring sulfonation depends on the route. UV-visible spectra pointed out that the level of the PAni protonation was dependent on the sulfonation route. A new appro
Materials Research. Publicado em: 14/10/2011
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12. Desenvolvimento de membranas mistas a base de poli(indeno) sulfonado e PVA reticulado com objetivo de aplicação em célula a combustível tipo PEM
The study on alternative membranes for use in fuel cells PEM (Proton Exchange Membrane) has been conducted by different research groups worldwide. As the commercial membranes still have high cost and performance limitations in certain operating conditions of fuel cells powered by hydrogen and alcohol. This study aimed to evaluate non-fluorinated membranes pr
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2011