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Registro Completo |
Biblioteca(s): |
Embrapa Algodão. |
Data corrente: |
26/08/1993 |
Data da última atualização: |
10/12/2007 |
Autoria: |
BELTRÃO, N. E. de M.; AZEVEDO, D. M. P. de. |
Título: |
Principios de controle de erva daninha com especial atencao a cotonicultura. |
Ano de publicação: |
1978 |
Fonte/Imprenta: |
Campina Grande: EMBRAPA-CNPA, 1978. |
Páginas: |
53p |
Idioma: |
Português |
Conteúdo: |
Importancia das ervas daninhas; Conceito de erva daninha; Caracteristicas e estagios de crescimento; Prejuizos causados ao homem; Disseminacao e propagacao; Origem de distribuicao; Habitat; Classificacao das ervas daninhas; Diferencas entre monocotiledonea edicotiledonea; Caracteres praticos para identificacao da familia; Botanica. |
Palavras-Chave: |
Brasil; Control; Controle; Nordeste; Weed. |
Thesagro: |
Algodão; Erva Daninha; Gossypium Hirsutum. |
Thesaurus Nal: |
cotton. |
Categoria do assunto: |
-- |
Marc: |
LEADER 00941nam a2200241 a 4500 001 1262832 005 2007-12-10 008 1978 bl uuuu 00u1 u #d 100 1 $aBELTRÃO, N. E. de M. 245 $aPrincipios de controle de erva daninha com especial atencao a cotonicultura. 260 $aCampina Grande: EMBRAPA-CNPA$c1978 300 $a53p 520 $aImportancia das ervas daninhas; Conceito de erva daninha; Caracteristicas e estagios de crescimento; Prejuizos causados ao homem; Disseminacao e propagacao; Origem de distribuicao; Habitat; Classificacao das ervas daninhas; Diferencas entre monocotiledonea edicotiledonea; Caracteres praticos para identificacao da familia; Botanica. 650 $acotton 650 $aAlgodão 650 $aErva Daninha 650 $aGossypium Hirsutum 653 $aBrasil 653 $aControl 653 $aControle 653 $aNordeste 653 $aWeed 700 1 $aAZEVEDO, D. M. P. de
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Registro original: |
Embrapa Algodão (CNPA) |
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Registro Completo
Biblioteca(s): |
Embrapa Instrumentação. |
Data corrente: |
28/11/2022 |
Data da última atualização: |
22/01/2024 |
Tipo da produção científica: |
Artigo em Periódico Indexado |
Circulação/Nível: |
A - 2 |
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. |
Afiliação: |
LUIZ ALBERTO COLNAGO, CNPDIA. |
Título: |
Head-to-tail and head-to-head molecular chains of poly(p-anisidine): Combined experimental and theoretical evaluation. |
Ano de publicação: |
2022 |
Fonte/Imprenta: |
Molecules, v. 27, a6326, 2022. |
Páginas: |
28 p. |
DOI: |
https://doi.org/10.3390/molecules27196326 |
Idioma: |
Inglês |
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 |
Palavras-Chave: |
Conjugated polymer; Multifractal analysis; Poly(p-anisidine). |
Categoria do assunto: |
-- |
URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/doc/1148841/1/P-Head-to-Tail-and-Head-to-Head-Molecular-Chains-of.pdf
|
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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