Effect of plasticizers and polymer blends for processing softwood kraft lignin as carbon fiber precursors
| Autor: | Tiina Nypelö, Martin A. Hubbe, Saad A. Khan, Trevor Treasure, Luke Hansen, Richard A. Venditti, Hasan Jameel, Ali Ayoub, Hou-min Chang |
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| Rok vydání: | 2020 |
| Předmět: |
chemistry.chemical_classification
Softwood Polymers and Plastics Carbonization fungi technology industry and agriculture Plasticizer food and beverages macromolecular substances 02 engineering and technology Polymer 010402 general chemistry 021001 nanoscience & nanotechnology complex mixtures 01 natural sciences 0104 chemical sciences chemistry.chemical_compound Differential scanning calorimetry chemistry Chemical engineering Lignin Polymer blend 0210 nano-technology Glass transition |
| Zdroj: | Cellulose. 28:1039-1053 |
| ISSN: | 1572-882X 0969-0239 |
| Popis: | Plasticizers depress the glass transition temperature (Tg) of polymers and produce a flowable material at lower temperatures. The use of plasticizers to depress Tg of lignin is important, since at high processing temperatures lignin crosslinks, making it intractable. The goal of this study was to assess plasticizers and polymer blends for the ability to retard a commercial softwood kraft lignin from crosslinking and also serve as thermal and rheological property modifiers during thermal processing in the attempt to produced moldable and spinnable lignin for lignin and carbon fiber products. The Tg of the lignin and the lignin mixed with various amounts of plasticizers and with different thermo-mechanical mixing were determined using differential scanning calorimetry. The Tg and the change in heat capacity at the glass transition (ΔCp) decreased and increased, respectively, about linearly within this plasticizers range with increased plasticizer weight percentage. Gel permeation chromatography results for extruded lignin as well as extruded lignin-plasticizer blends with glycerol, N-allyurea, citric acid with and without sodium hypophosphite, and oleic acid indicate that the presence of these materials reduced the rate of molecular weight increase at temperatures between 100 and 200 °C. Continuous, homogenous films and fibers could be produced by thermal processing with plasticized lignin samples and plasticized lignin-polymer blends, but not with lignin alone. These fibers could be carbonized, yielding up to about 50% of carbon. The present findings have shown the advantages of plasticizers in thermally processing a commercial softwood kraft lignin. |
| Databáze: | OpenAIRE |
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