Reactivity of Aliphatic and Phenolic Hydroxyl Groups in Kraft Lignin towards 4,4′ MDI
| Autor: | Demetrio Jackson dos Santos, Leonardo Dalseno Antonino, Rogério Ramos de Sousa Junior, Guilherme Elias Saltarelli Garcia, Lara Basilio Tavares, Luara Carneiro Gobbo, Julia Rocha Gouveia |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Chemical structure
Pharmaceutical Science macromolecular substances engineering.material lignin-based polyurethanes Article hydroxyl group Analytical Chemistry Ftir spectra lcsh:QD241-441 chemistry.chemical_compound lcsh:Organic chemistry Drug Discovery Organic chemistry Lignin Reactivity (chemistry) Experimental work Physical and Theoretical Chemistry Kraft lignin Chemistry Organic Chemistry Chemistry (miscellaneous) engineering Molecular Medicine Biopolymer chemical reactivity |
| Zdroj: | Molecules, Vol 26, Iss 2131, p 2131 (2021) Molecules Volume 26 Issue 8 |
| ISSN: | 1420-3049 |
| Popis: | Several efforts have been dedicated to the development of lignin-based polyurethanes (PU) in recent years. The low and heterogeneous reactivity of lignin hydroxyl groups towards diisocyanates, arising from their highly complex chemical structure, limits the application of this biopolymer in PU synthesis. Besides the well-known differences in the reactivity of aliphatic and aromatic hydroxyl groups, experimental work in which the reactivity of both types of hydroxyl, especially the aromatic ones present in syringyl (S-unit), guaiacyl (G-unit), and p-hydroxyphenyl (H-unit) building units are considered and compared, is still lacking in the literature. In this work, the hydroxyl reactivity of two kraft lignin grades towards 4,4′-diphenylmethane diisocyanate (MDI) was investigated. 31P NMR allowed the monitoring of the reactivity of each hydroxyl group in the lignin structure. FTIR spectra revealed the evolution of peaks related to hydroxyl consumption and urethane formation. These results might support new PU developments, including the use of unmodified lignin and the synthesis of MDI-functionalized biopolymers or prepolymers. |
| Databáze: | OpenAIRE |
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