| Full text | |
| Author(s): |
Paiva, Germana M. S.
[1]
;
Duarte, Luis G. T. A.
[1]
;
Faleiros, Marcelo M.
[1]
;
Atvars, Teresa D. Z.
[1]
;
Felisberti, Maria Isabel
[1]
Total Authors: 5
|
| Affiliation: | [1] Univ Estadual Campinas, Inst Chem, POB 6154, BR-13084971 Campinas, SP - Brazil
Total Affiliations: 1
|
| Document type: | Journal article |
| Source: | JOURNAL OF MOLECULAR LIQUIDS; v. 337, SEP 1 2021. |
| Web of Science Citations: | 0 |
| Abstract | |
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) | |
| FAPESP's process: | 15/25406-5 - Organizing matter: colloids formed by association of surfactants, polymers and nanoparticles |
| Grantee: | Watson Loh |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 13/16245-2 - Photophysical properties of thin films of conjugated polymers |
| Grantee: | Teresa Dib Zambon Atvars |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 15/08541-6 - Nuclear magnetic resonance spectroscopy: beyond molecular structure assignment |
| Grantee: | Claudio Francisco Tormena |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 16/11197-8 - Polyurethanes tri- and tetra blocks functionalized with azo group: synthesis, characterization and evaluation of potential as photo-responsive materials |
| Grantee: | Germana Maria Santos Paiva |
| Support Opportunities: | Scholarships in Brazil - Doctorate |