Effect of Amine Type on Lignin Modification to Evaluate Its Reactivity in Polyol Construction for Non-Isocyanate Polyurethanes (NIPU)

Abstract

Polyols are groups of organic compounds which contain carbon and are randomly linked to other atoms, especially carbon-carbon and carbon-hydrogen. These compounds are mainly used as reactants to make other polymers. Among biopolymers, lignin is regarded as the base of a new polymer in polyol construction. The present study aimed to investigate the effects of amine type (diethylenetriamine and ethylenediamine) on the modification of lignin-based polyols, so as to provide an alternative to petroleum polyols and, in turn, increase functional groups and reduce their harm to humans' health and the environment. To this aim, first, lignin was extracted from raw liquor. Next, the extracted lignin was reacted with diethylenetriamine (DETA) and ethylenediamine (EDA). Finally, the Mannich method was used for the reaction between amine lignin and propylene carbonate. The results of the Fourier Transform Infrared (FTIR) spectroscopy analysis showed that modification with DETA led to more structural change in lignin and peak 1100 indicates the presence of C-O bond related to urethane bonds in modified lignin. Moreover, adding propylene carbonate to aminated lignin did not result in much change in the results of the FTIR analysis. Additionally, urethane bonds can be seen in the results of GPC at 400°C-500°C. Furthermore, a slight decrease in thermal stability was observed in lignin modified with amine and propylene carbonate, compared to the raw lignin sample.

Latest Advancements in the Development of High-Performance Lignin- and Tannin-Based Non-Isocyanate Polyurethane Adhesive for Wood Composites

“…The use of kraft lignin (KL) as a polyol alternative within the NIPU matrix has the potential to enhance the aromatic composition of the resultant polymer. KL exhibits a degree of stability at elevated temperatures and functions as a thermosetting material, owing to its aromatic and crosslinked nature [10,23,25,28,61,62]. Consequently, it is anticipated that the incorporation of lignin will enhance the glass transition temperature and thermal stability of the adhesive.…”

“…Recent years have seen a surge in commercial and academic interest in the development of NIPUs for renewable resources [19,20]. NIPUs can be produced from polyols derived from renewable resources, including lignin [3,[21][22][23][24][25][26][27][28] and tannin [3,24,[29][30][31][32][33][34][35][36][37]. Because lignin and tannin are natural This review article examines scholarly articles published between January 2010 and April 2023 in the Scopus database on the topic of bio-based NIPU adhesives derived from lignin and tannin from various perspectives and methodologies (Figure 1).…”

“…Recent years have seen a surge in commercial and academic interest in the development of NIPUs for renewable resources [19,20]. NIPUs can be produced from polyols derived from renewable resources, including lignin [3,[21][22][23][24][25][26][27][28] and tannin [3,24,[29][30][31][32][33][34][35][36][37]. Because lignin and tannin are natural polymer molecules derived from plants, they are the most prevalent renewable adhesive sources.…”

Lignin-Based Polyurethanes from the Blocked Isocyanate Approach: Synthesis and Characterization

“…Lignin is the second most abundant biopolymer on the planet and the most abundant aromatic one . It is found in plant cells together with cellulose and hemicellulose.…”

“…6 Lignin is the second most abundant biopolymer on the planet and the most abundant aromatic one. 7 It is found in plant cells together with cellulose and hemicellulose. Its aromatic structure is composed of three basic phenylpropane units, guaiacyl (G-unit), syringyl (S-unit), and p-hydroxyphenyl (H-unit), which are derived from coniferyl, sinapyl, and pcoumaryl alcohol, respectively.…”