| Full text | |
| Author(s): |
Antonino, Leonardo Dalseno
;
Gouveia, Julia Rocha
;
de Sousa Junior, Rogerio Ramos
;
Garcia, Guilherme Elias Saltarelli
;
Gobbo, Luara Carneiro
;
Tavares, Lara Basilio
;
dos Santos, Demetrio Jackson
Total Authors: 7
|
| Document type: | Journal article |
| Source: | Molecules; v. 26, n. 8, p. 12-pg., 2021-04-01. |
| Abstract | |
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. P-31 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. (AU) | |
| FAPESP's process: | 17/22936-9 - TEMPERATURE MODULATED OPTICAL REFRACTOMETRY: A MOLECULAR PERSPECTIVE ON CURING KINETIC AND PHASE SEPARATION OF LIGNIN-BASED POLYURETHANES |
| Grantee: | Demetrio Jackson dos Santos |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 19/05460-6 - Thermoactive polyurethane adhesive based on modified kraft lignin |
| Grantee: | Leonardo Dalseno Antonino |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |
| FAPESP's process: | 20/00876-7 - Development of sustainable filaments for 3D Printing from PLA and kraft lignin |
| Grantee: | Júlia Rocha Gouveia |
| Support Opportunities: | Research Grants - Innovative Research in Small Business - PIPE |