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Registro Completo |
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Biblioteca(s): |
Embrapa Algodão. |
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Data corrente: |
14/01/2020 |
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Data da última atualização: |
20/01/2020 |
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Tipo da produção científica: |
Artigo em Periódico Indexado |
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Autoria: |
VASCONCELOS, N. F.; FEITOSA, J. P. A.; ANDRADE, F. K.; MIRANDA, M. A. R.; SASAKI, J. M.; MORAIS, J. P. S.; SILVA, L. M. A. e; CANUTO, K. M.; ROSA, M. de F. |
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Afiliação: |
Niédja Fittipaldi Vasconcelos, Universidade Federal do Ceará - UFC/Departamento de Química; Judith Pessoa Andrade Feitosa, Universidade Federal do Ceará - UFC/Departamento de Química; Fábia Karine Andrade, Universidade Federal do Ceará - UFC/Departamento de Engenharia Química; Marcus Aurélio Ribeiro Miranda, Universidade Federal do Ceará - UFC/Departamento de Física; José Marcos Sasaki, Universidade Federal do Ceará - UFC/Departamento de Física; JOAO PAULO SARAIVA MORAIS, CNPA; LORENA MARA ALEXANDRE E SILVA, CNPAT; KIRLEY MARQUES CANUTO, CNPAT; MORSYLEIDE DE FREITAS ROSA, CNPAT. |
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Título: |
Chemically modified cellulose nanocrystals as polyanion for preparation of polyelectrolyte complex. |
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Ano de publicação: |
2019 |
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Fonte/Imprenta: |
Cellulose, v. 26, n. 3, p. 1725-1746, February 2019. |
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Idioma: |
Inglês |
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Conteúdo: |
Bacterial cellulose nanocrystals (BCNCs) have hydrophilic surfaces due to hydroxyl groups but are water-insoluble. The carboxymethylation improves the solubility of cellulose in polar media through the insertion of carboxymethyl groups. This study aims to evaluate the use of two different alcoholic solvents in the carboxymethylation reaction of BCNCs: ethanol and isopropanol. BCNCs were obtained under two hydrolysis conditions: sulfuric acid (BCNC-S) and combination of sulfuric and hydrochloric acids (BCNC-S/Cl). Two techniques (NMR and titration) were used to determine the degree of substitution (DS) values. Carboxymethylation of BCNC-S/Cl led to high DS compared to BCNC-S and the use of isopropanol promoted an even greater DS. The thermal properties were not affected after the chemical modification. However, functionalization provided an increase in the negative charge density at the surface of nanostructures and a change in the crystal structure (cellulose type Ia for amorphous), making this material a potential polyanion for the synthesis of polyelectrolyte complexes (PECs). The micrographs showed that the nanocrystals became soluble after carboxymethylation. Carboxymethylated bacterial cellulose nanocrystals hydrolyzed through the mixture of inorganic acids and modified using isopropanol (CBCNC-S/Cl-IPA) was a suitable polyanion to produce PECs with chitosan. The PECs produced had particle size ranging from 276 to 588 nm and zeta potential ranging from - 24.3 to + 39.0 mV. MenosBacterial cellulose nanocrystals (BCNCs) have hydrophilic surfaces due to hydroxyl groups but are water-insoluble. The carboxymethylation improves the solubility of cellulose in polar media through the insertion of carboxymethyl groups. This study aims to evaluate the use of two different alcoholic solvents in the carboxymethylation reaction of BCNCs: ethanol and isopropanol. BCNCs were obtained under two hydrolysis conditions: sulfuric acid (BCNC-S) and combination of sulfuric and hydrochloric acids (BCNC-S/Cl). Two techniques (NMR and titration) were used to determine the degree of substitution (DS) values. Carboxymethylation of BCNC-S/Cl led to high DS compared to BCNC-S and the use of isopropanol promoted an even greater DS. The thermal properties were not affected after the chemical modification. However, functionalization provided an increase in the negative charge density at the surface of nanostructures and a change in the crystal structure (cellulose type Ia for amorphous), making this material a potential polyanion for the synthesis of polyelectrolyte complexes (PECs). The micrographs showed that the nanocrystals became soluble after carboxymethylation. Carboxymethylated bacterial cellulose nanocrystals hydrolyzed through the mixture of inorganic acids and modified using isopropanol (CBCNC-S/Cl-IPA) was a suitable polyanion to produce PECs with chitosan. The PECs produced had particle size ranging from 276 to 588 nm and zeta potential ranging from - 24.3 to + 39.0 ... Mostrar Tudo |
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Palavras-Chave: |
Carboxymethylation; Polyelectrolytic complexes. |
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Thesaurus Nal: |
Chitosan; Hydrolysis; Nanocrystals. |
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Categoria do assunto: |
-- |
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URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/item/208702/1/Chemically-modified-cellulose.pdf
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Marc: |
LEADER 02321naa a2200277 a 4500
001 2118682
005 2020-01-20
008 2019 bl uuuu u00u1 u #d
100 1 $aVASCONCELOS, N. F.
245 $aChemically modified cellulose nanocrystals as polyanion for preparation of polyelectrolyte complex.$h[electronic resource]
260 $c2019
520 $aBacterial cellulose nanocrystals (BCNCs) have hydrophilic surfaces due to hydroxyl groups but are water-insoluble. The carboxymethylation improves the solubility of cellulose in polar media through the insertion of carboxymethyl groups. This study aims to evaluate the use of two different alcoholic solvents in the carboxymethylation reaction of BCNCs: ethanol and isopropanol. BCNCs were obtained under two hydrolysis conditions: sulfuric acid (BCNC-S) and combination of sulfuric and hydrochloric acids (BCNC-S/Cl). Two techniques (NMR and titration) were used to determine the degree of substitution (DS) values. Carboxymethylation of BCNC-S/Cl led to high DS compared to BCNC-S and the use of isopropanol promoted an even greater DS. The thermal properties were not affected after the chemical modification. However, functionalization provided an increase in the negative charge density at the surface of nanostructures and a change in the crystal structure (cellulose type Ia for amorphous), making this material a potential polyanion for the synthesis of polyelectrolyte complexes (PECs). The micrographs showed that the nanocrystals became soluble after carboxymethylation. Carboxymethylated bacterial cellulose nanocrystals hydrolyzed through the mixture of inorganic acids and modified using isopropanol (CBCNC-S/Cl-IPA) was a suitable polyanion to produce PECs with chitosan. The PECs produced had particle size ranging from 276 to 588 nm and zeta potential ranging from - 24.3 to + 39.0 mV.
650 $aChitosan
650 $aHydrolysis
650 $aNanocrystals
653 $aCarboxymethylation
653 $aPolyelectrolytic complexes
700 1 $aFEITOSA, J. P. A.
700 1 $aANDRADE, F. K.
700 1 $aMIRANDA, M. A. R.
700 1 $aSASAKI, J. M.
700 1 $aMORAIS, J. P. S.
700 1 $aSILVA, L. M. A. e
700 1 $aCANUTO, K. M.
700 1 $aROSA, M. de F.
773 $tCellulose$gv. 26, n. 3, p. 1725-1746, February 2019.
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Registro original: |
Embrapa Algodão (CNPA) |
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 | Acesso ao texto completo restrito à biblioteca da Embrapa Agrobiologia. Para informações adicionais entre em contato com cnpab.biblioteca@embrapa.br. |
Registro Completo
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Biblioteca(s): |
Embrapa Agrobiologia. |
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Data corrente: |
25/07/2005 |
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Data da última atualização: |
25/07/2005 |
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Autoria: |
ARAÚJO, E. S.; MEDEIROS, A. F. A.; URQUIAGA, S.; BODDEY, R. M.; ALVES, B. J. R. |
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Título: |
Quantificação do N acumulado nas raízes da soja através do uso do isótopo 15N. |
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Ano de publicação: |
2003 |
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Fonte/Imprenta: |
In: CONGRESSO BRASILEIRO DE CIÊNCIA DO SOLO, 29., 2003, Ribeirão Preto. Resumos... Botucatu: SBCS, 2003. 4 p. CD ROM. |
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Idioma: |
Português |
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Palavras-Chave: |
N. |
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Thesagro: |
Nitrogênio; Soja. |
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Thesaurus NAL: |
nitrogen; soybeans. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 00653naa a2200217 a 4500
001 1628278
005 2005-07-25
008 2003 bl --- 0-- u #d
100 1 $aARAÚJO, E. S.
245 $aQuantificação do N acumulado nas raízes da soja através do uso do isótopo 15N.
260 $c2003
650 $anitrogen
650 $asoybeans
650 $aNitrogênio
650 $aSoja
653 $aN
700 1 $aMEDEIROS, A. F. A.
700 1 $aURQUIAGA, S.
700 1 $aBODDEY, R. M.
700 1 $aALVES, B. J. R.
773 $tIn: CONGRESSO BRASILEIRO DE CIÊNCIA DO SOLO, 29., 2003, Ribeirão Preto. Resumos... Botucatu: SBCS, 2003. 4 p. CD ROM.
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