Data/hora: 05/06/2024 11:22:37

Biblioteca(s): | Embrapa Instrumentação.
Tipo da produção científica: | Artigo em Periódico Indexado
Circulação/Nível: | A - 2
Data corrente: | 28/11/2022
Data da última atualização: | 22/01/2024
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 2&#952; = 10.0?30.0&#9702;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 &#957;(C?H), &#957;(N?H), &#957;(C?O), and &#957;(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&#8722;9 S.cm&#8722;1 and 3.90 × 10&#8722;14 S.cm&#8722;1, respectively, for PPA1HT and PPA16HT-HH.
Palavras-Chave: | Conjugated polymer; Multifractal analysis; Poly(p-anisidine).
Categoria do assunto: | --
URL: | http://ainfo.cnptia.embrapa.br/digital/bitstream/doc/1148841/1/P-Head-to-Tail-and-Head-to-Head-Molecular-Chains-of.pdf
Registro original: | Embrapa Instrumentação (CNPDIA)
Exemplares: | CNPDIA - (18133-1) - UPC - AP - DD - PROCI.22/164 -  - 2022/169 - DIS