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Updated: May 30, 2025
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Quantitative 31P NMR Analysis of Lignins and Tannins
Published on: August 2, 2021
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A Systematic Study of the Structural Properties of Technical Lignins
Keiti Gilioli Tosin1, Noriê Finimundi2, Matheus Poletto1
1Postgraduate Program in Engineering of Processes and Technologies (PGEPROTEC), University of Caxias do Sul (UCS), Caxias do Sul 95070-560, Brazil.
Polymers
|January 25, 2025
Summary
Technical lignins, like sodium lignosulfonate (LGNa) and magnesium lignosulfonate (LGMg), offer sustainable feedstock options. Higher phenolic hydroxyl groups in lignins correlate with altered hydrogen bonding, thermal stability, and combustion properties, impacting industrial applications.
Area of Science:
- Biomass valorization
- Materials science
- Sustainable chemistry
Background:
- Technical lignins are abundant, renewable resources with unique chemical structures.
- Understanding the structure-property relationships of technical lignins is crucial for their industrial utilization.
- Sodium lignosulfonate (LGNa) and magnesium lignosulfonate (LGMg) are key examples of technical lignins.
Purpose of the Study:
- To investigate the relationship between the structure and properties of two technical lignins: LGNa and LGMg.
- To elucidate how phenolic hydroxyl group content influences the characteristics of lignosulfonates.
- To assess the implications of these structural variations for industrial applications.
Main Methods:
- Comprehensive characterization of LGNa and LGMg, including morphological, chemical, physical, and thermal analyses.
- Evaluation of hydrogen bonding (intramolecular and intermolecular) and its energy.
- Determination of thermal stability and combustion properties (combustion index).
Main Results:
- Lignin with higher phenolic hydroxyl groups (LGMg) exhibited increased intramolecular hydrogen bonding.
- An elevated hydrogen bond energy was observed in LGMg without significant changes in bond distances.
- Higher phenolic hydroxyl content in LGMg correlated with reduced thermal stability and a threefold higher combustion index compared to LGNa.
Conclusions:
- Phenolic hydroxyl groups are a critical factor influencing the properties of technical lignins.
- The structural characteristics, particularly phenolic hydroxyl content, dictate the suitability of lignosulfonates for specific industrial applications.
- Tailoring lignin structure through control of phenolic hydroxyl groups can optimize performance in various industrial contexts.
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