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Lignin polyurethane aerogels synthesis as super insulating materials via supercritical CO2 drying
Citation Link: https://doi.org/10.15480/882.5109
Publikationstyp
Conference Poster not in Proceedings
Date Issued
2022
Sprache
English
Author(s)
Institut
TORE-DOI
Aerogels are nanoporous materials with high surface and very low thermal conductivity which present it as a promising candidate for thermal insulating materials [1]. The nanoscale porous structure is synthesized using supercritical CO2 drying (Sc-CO2) method which permits eliminating the solvent from the gel at zero surface tension without collapsing its structure [2], [3]. Specifically, Organic aerogels has an advantage over its inorganic counterparts mainly due to their higher mechanical stability [4].
Recently, there has been a driven interest to produce organic aerogels such as polyurethane aerogels from various biomass sources. [5] Lignin is one of the most investigated bio-based polyols for the production of polyurethane aerogels due to the abundance of hydroxyl groups in its aromatic structure [6]. However, the low solubility, low reactivity and high polydispersity emerge as challenges for the synthesis of lignin polyurethane aerogels [7].Thus, the resulting lignin polyurethane aerogels suffers from low surface area, high shrinkage and high thermal conductivity.
This study aims on understanding the complexity lignin introduces into the synthesis of polyurethane aerogels with the goal of resolving the previously mentioned challenges. Preliminary studies showed the predominating factors to be lignin type, lignin-solvent interaction and monomer concertation. The experimental part focuses on understanding how these factors influences the gelation kinetics, morphology and structure evolution and crosslinking density. The results are further interpreted by measuring porosity, elemental analysis, volumetric shrinkage and thermal conductivity.
Recently, there has been a driven interest to produce organic aerogels such as polyurethane aerogels from various biomass sources. [5] Lignin is one of the most investigated bio-based polyols for the production of polyurethane aerogels due to the abundance of hydroxyl groups in its aromatic structure [6]. However, the low solubility, low reactivity and high polydispersity emerge as challenges for the synthesis of lignin polyurethane aerogels [7].Thus, the resulting lignin polyurethane aerogels suffers from low surface area, high shrinkage and high thermal conductivity.
This study aims on understanding the complexity lignin introduces into the synthesis of polyurethane aerogels with the goal of resolving the previously mentioned challenges. Preliminary studies showed the predominating factors to be lignin type, lignin-solvent interaction and monomer concertation. The experimental part focuses on understanding how these factors influences the gelation kinetics, morphology and structure evolution and crosslinking density. The results are further interpreted by measuring porosity, elemental analysis, volumetric shrinkage and thermal conductivity.
DDC Class
620: Ingenieurwissenschaften
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