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Registro Completo |
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Biblioteca(s): |
Embrapa Semiárido. |
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Data corrente: |
14/09/2004 |
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Data da última atualização: |
10/10/2022 |
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Tipo da produção científica: |
Documentos |
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Autoria: |
OLIVEIRA, C. A. V.; CORREIA, R. C. |
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Afiliação: |
CARLOS ALBERTO VASCONCELOS OLIVEIRA, CPATSA; REBERT COELHO CORREIA, CPATSA. |
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Título: |
Tipificação de pequenos produtores do semi-árido nordestino. |
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Ano de publicação: |
2004 |
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Fonte/Imprenta: |
Petrolina: Embrapa Semi-Árido, 2004. |
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Descrição Física: |
1 CD-ROM. |
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Idioma: |
Português |
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Conteúdo: |
Base de dados com informações sobre sistema de produção praticados pelos pequenos produtores e da agricultura familiar na região semiárida; Tipificação dos pequenos produtores; Tipificação da agricultura familiar. |
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Palavras-Chave: |
Banco de dados; Nordeste; Semiárido; Tipificação de pequeno produtor. |
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Thesagro: |
Agricultura Familiar; Pequeno Produtor; Sistema de Produção. |
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Thesaurus Nal: |
Family farms; Farm families; Farm inventories; Farm labor; Farm management. |
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Categoria do assunto: |
B Sociologia Rural |
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Marc: |
LEADER 00979nam a2200277 a 4500
001 1154028
005 2022-10-10
008 2004 bl uuuu 00u1 u #d
100 1 $aOLIVEIRA, C. A. V.
245 $aTipificação de pequenos produtores do semi-árido nordestino.
260 $aPetrolina: Embrapa Semi-Árido$c2004
300 $c1 CD-ROM.
520 $aBase de dados com informações sobre sistema de produção praticados pelos pequenos produtores e da agricultura familiar na região semiárida; Tipificação dos pequenos produtores; Tipificação da agricultura familiar.
650 $aFamily farms
650 $aFarm families
650 $aFarm inventories
650 $aFarm labor
650 $aFarm management
650 $aAgricultura Familiar
650 $aPequeno Produtor
650 $aSistema de Produção
653 $aBanco de dados
653 $aNordeste
653 $aSemiárido
653 $aTipificação de pequeno produtor
700 1 $aCORREIA, R. C.
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Registro original: |
Embrapa Semiárido (CPATSA) |
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Registro Completo
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Biblioteca(s): |
Embrapa Instrumentação. |
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Data corrente: |
28/11/2022 |
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Data da última atualização: |
22/01/2024 |
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Tipo da produção científica: |
Artigo em Periódico Indexado |
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Circulação/Nível: |
A - 2 |
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Autoria: |
OLIVEIRA, L. R. de; GONÇALVES, D. S.; CAROLINO, A. S.; FACCINATTO, W. M.; MENEZES. D. C.; DIAS, C. O.; COLNAGO, L. A.; RUIZ, Y. L.; IU, S. T.; FONSECA FILHO, H. D.; CHAUDHURI, P.; CAMPELO, P. H.; MASCARENHAS, I. P.; SANCHES, E. A. |
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Afiliação: |
LUIZ ALBERTO COLNAGO, CNPDIA. |
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Título: |
Head-to-tail and head-to-head molecular chains of poly(p-anisidine): Combined experimental and theoretical evaluation. |
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Ano de publicação: |
2022 |
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Fonte/Imprenta: |
Molecules, v. 27, a6326, 2022. |
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Páginas: |
28 p. |
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DOI: |
https://doi.org/10.3390/molecules27196326 |
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Idioma: |
Inglês |
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Conteúdo: |
: Poly(p-anisidine) (PPA) is a polyaniline derivative presenting a methoxy (?OCH3) group at the para position of the phenyl ring. Considering the important role of conjugated polymers in novel technological applications, a systematic, combined experimental and theoretical investigation was performed to obtain more insight into the crystallization process of PPA. Conventional oxidative polymerization of p-anisidine monomer was based on a central composite rotational design (CCRD).The effects of the concentration of the monomer, ammonium persulfate (APS), and HCl on the percentage of crystallinity were considered. Several experimental techniques such as X-ray Diffraction(XRD), Scanning Electron Microscopy (SEM), multifractal analysis, Nuclear Magnetic Resonance(13C NMR), Fourier-transform Infrared spectroscopy (FTIR), and complex impedance spectroscopyanalysis, in addition to Density Functional Theory (DFT), were employed to perform a systematic investigation of PPA. The experimental treatments resulted in different crystal structures with a percentage of crystallinity ranging from (29.2 ± 0.6)% (PPA1HT) to (55.1 ± 0.2)% (PPA16HT-HH). A broad halo in the PPA16HT-HH pattern from 2θ = 10.0?30.0◦suggested a reduced crystallinity. Needle and globular-particle morphologies were observed in both samples; the needle morphology might have been related to the crystalline contribution. A multifractal analysis showed that the PPA surface became more complex when the crystallinity was reduced. The proposed molecular structures of PPA were supported by the high-resolution 13C NMR results, allowing us to access the percentage of head-to-tail (HT) and head-to-head (HH) molecular structures. When comparing the calculated and experimental FTIR spectra, the most pronounced changes were observed in ν(C?H), ν(N?H), ν(C?O), and ν(C?N?C) due to the influence of counterions on the polymer backbone as well as the different mechanisms of polymerization. Finally, a significant difference in the electrical conductivitywas observed in the range of 1.00 × 10−9 S.cm−1 and 3.90 × 10−14 S.cm−1, respectively, for PPA1HT and PPA16HT-HH. Menos: Poly(p-anisidine) (PPA) is a polyaniline derivative presenting a methoxy (?OCH3) group at the para position of the phenyl ring. Considering the important role of conjugated polymers in novel technological applications, a systematic, combined experimental and theoretical investigation was performed to obtain more insight into the crystallization process of PPA. Conventional oxidative polymerization of p-anisidine monomer was based on a central composite rotational design (CCRD).The effects of the concentration of the monomer, ammonium persulfate (APS), and HCl on the percentage of crystallinity were considered. Several experimental techniques such as X-ray Diffraction(XRD), Scanning Electron Microscopy (SEM), multifractal analysis, Nuclear Magnetic Resonance(13C NMR), Fourier-transform Infrared spectroscopy (FTIR), and complex impedance spectroscopyanalysis, in addition to Density Functional Theory (DFT), were employed to perform a systematic investigation of PPA. The experimental treatments resulted in different crystal structures with a percentage of crystallinity ranging from (29.2 ± 0.6)% (PPA1HT) to (55.1 ± 0.2)% (PPA16HT-HH). A broad halo in the PPA16HT-HH pattern from 2θ = 10.0?30.0◦suggested a reduced crystallinity. Needle and globular-particle morphologies were observed in both samples; the needle morphology might have been related to the crystalline contribution. A multifractal analysis showed that the PPA surface became more complex when the crystallin... Mostrar Tudo |
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Palavras-Chave: |
Conjugated polymer; Multifractal analysis; Poly(p-anisidine). |
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Categoria do assunto: |
-- |
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URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/doc/1148841/1/P-Head-to-Tail-and-Head-to-Head-Molecular-Chains-of.pdf
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Marc: |
LEADER 03197naa a2200337 a 4500
001 2148841
005 2024-01-22
008 2022 bl uuuu u00u1 u #d
024 7 $ahttps://doi.org/10.3390/molecules27196326$2DOI
100 1 $aOLIVEIRA, L. R. de
245 $aHead-to-tail and head-to-head molecular chains of poly(p-anisidine)$bCombined experimental and theoretical evaluation.$h[electronic resource]
260 $c2022
300 $a28 p.
520 $a: Poly(p-anisidine) (PPA) is a polyaniline derivative presenting a methoxy (?OCH3) group at the para position of the phenyl ring. Considering the important role of conjugated polymers in novel technological applications, a systematic, combined experimental and theoretical investigation was performed to obtain more insight into the crystallization process of PPA. Conventional oxidative polymerization of p-anisidine monomer was based on a central composite rotational design (CCRD).The effects of the concentration of the monomer, ammonium persulfate (APS), and HCl on the percentage of crystallinity were considered. Several experimental techniques such as X-ray Diffraction(XRD), Scanning Electron Microscopy (SEM), multifractal analysis, Nuclear Magnetic Resonance(13C NMR), Fourier-transform Infrared spectroscopy (FTIR), and complex impedance spectroscopyanalysis, in addition to Density Functional Theory (DFT), were employed to perform a systematic investigation of PPA. The experimental treatments resulted in different crystal structures with a percentage of crystallinity ranging from (29.2 ± 0.6)% (PPA1HT) to (55.1 ± 0.2)% (PPA16HT-HH). A broad halo in the PPA16HT-HH pattern from 2θ = 10.0?30.0◦suggested a reduced crystallinity. Needle and globular-particle morphologies were observed in both samples; the needle morphology might have been related to the crystalline contribution. A multifractal analysis showed that the PPA surface became more complex when the crystallinity was reduced. The proposed molecular structures of PPA were supported by the high-resolution 13C NMR results, allowing us to access the percentage of head-to-tail (HT) and head-to-head (HH) molecular structures. When comparing the calculated and experimental FTIR spectra, the most pronounced changes were observed in ν(C?H), ν(N?H), ν(C?O), and ν(C?N?C) due to the influence of counterions on the polymer backbone as well as the different mechanisms of polymerization. Finally, a significant difference in the electrical conductivitywas observed in the range of 1.00 × 10−9 S.cm−1 and 3.90 × 10−14 S.cm−1, respectively, for PPA1HT and PPA16HT-HH.
653 $aConjugated polymer
653 $aMultifractal analysis
653 $aPoly(p-anisidine)
700 1 $aGONÇALVES, D. S.
700 1 $aCAROLINO, A. S.
700 1 $aFACCINATTO, W. M.
700 1 $aMENEZES. D. C.
700 1 $aDIAS, C. O.
700 1 $aCOLNAGO, L. A.
700 1 $aRUIZ, Y. L.
700 1 $aIU, S. T.
700 1 $aFONSECA FILHO, H. D.
700 1 $aCHAUDHURI, P.
700 1 $aCAMPELO, P. H.
700 1 $aMASCARENHAS, I. P.
700 1 $aSANCHES, E. A.
773 $tMolecules$gv. 27, a6326, 2022.
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