| Texto completo | |
| Autor(es): |
Paiva, Germana M. S.
[1]
;
Duarte, Luis G. T. A.
[1]
;
Faleiros, Marcelo M.
[1]
;
Atvars, Teresa D. Z.
[1]
;
Felisberti, Maria Isabel
[1]
Número total de Autores: 5
|
| Afiliação do(s) autor(es): | [1] Univ Estadual Campinas, Inst Chem, POB 6154, BR-13084971 Campinas, SP - Brazil
Número total de Afiliações: 1
|
| Tipo de documento: | Artigo Científico |
| Fonte: | JOURNAL OF MOLECULAR LIQUIDS; v. 337, SEP 1 2021. |
| Citações Web of Science: | 0 |
| Resumo | |
This article presents the synthesis and structural, thermal and dynamic mechanical characterization of segmented polyurethane - PCLDHAB - based on poly(caprolactone)-diol (PCL-diol) as a flexible segment, and polyurethane-diol (PU-diol) as a rigid segment based on 2,2'-dihydroxyazobenzene (2,2'-DHAB). While the precursors PU-diol and PCL-diol are rigid and waxy materials, respectively, PCLDHAB is a flexible, semi-crystalline polymer, which has a heterogeneous amorphous phase. To better understand the absorption spectra of the polyurethanes, theoretical predictions by DFT and TD-DFT of a model molecule in DMF (implicitly added) were carried out. The model molecule was a fragment of the hard segment of the polyurethane's chain, containing one 2,2'-DHAB and two 4'-isocyanate-4'-methylbenzene fragments, bonded to each other by carbamate bonds, the 4-isocyanate-4'-metylbenzene-alt-2,2'-dihydroxyazoben zene. Similar to 2,2'-DHAB, PU-diol and PCLDHAB do not show photoisomerization, however they emit fluorescence. 2,2'-DHAB segments in the polyurethane chains present different conformations with distinct spectroscopic characteristics. However, the conformer's proportion in the polymer chains differs from the 2,2'-DHAB monomers in DMF solution. 2,2'-DHAB emits in two ranges in the UV-vis spectrum while its polyurethanes emit in three ranges, covering a broader wavelength range from ultraviolet to visible. (C) 2021 Elsevier B.V. All rights reserved. (AU) | |
| Processo FAPESP: | 15/25406-5 - Organizando a matéria: colóides formados por associação de surfactantes, polímeros e nanopartículas |
| Beneficiário: | Watson Loh |
| Modalidade de apoio: | Auxílio à Pesquisa - Temático |
| Processo FAPESP: | 13/16245-2 - Propriedades fotofísicas de filmes finos de polímeros conjugados |
| Beneficiário: | Teresa Dib Zambon Atvars |
| Modalidade de apoio: | Auxílio à Pesquisa - Regular |
| Processo FAPESP: | 15/08541-6 - Ressonância magnética nuclear: além da determinação estrutural |
| Beneficiário: | Claudio Francisco Tormena |
| Modalidade de apoio: | Auxílio à Pesquisa - Temático |
| Processo FAPESP: | 16/11197-8 - Poliuretanas TRI e tetrablocos funcionalizadas com grupo azo: síntese, caracterização e avaliação do potencial como material fotorresponsivo |
| Beneficiário: | Germana Maria Santos Paiva |
| Modalidade de apoio: | Bolsas no Brasil - Doutorado |