| Autor: |
Le Dai Duong, Gi-Yong Nam, Joon-Suk Oh, In-Kyung Park, Nguyen Dang Luong, Ho-Kyu Yoon, Seong-Hoon Lee, Youngkwan Lee, Ju-Ho Yun, Chong-Gu Lee, Suk-Ho Hwang, Jae-Do Nam |
| Jazyk: |
angličtina |
| Rok vydání: |
2014 |
| Předmět: |
|
| Zdroj: |
BioResources, Vol 9, Iss 2, Pp 2359-2371 (2014) |
| Druh dokumentu: |
article |
| ISSN: |
1930-2126 |
| DOI: |
10.15376/biores.9.2.2359-2371 |
| Popis: |
A high molecular-weight thermoplastic lignin-based polymer was successfully synthesized by adjusting the degree of polymerization while inducing linear growth of lignin macromers via methylene diphenyldiisocyanate. The thermoplastic lignin-urethane polymer was desirably achieved in a narrow range of reaction conditions of 2.5 to 3.5 h at 80 oC in this study, and the molecular weight of the resulting lignin-based polyurethanes (LigPU) reached as high as 912,000 g/mole, which is far above any reported values of lignin-based polymer derivatives. The thermal stability of LigPU was greatly improved by the urethane polymerization, giving the initial degradation temperature (T2%) at 204 °C, which should be compared with T2% = 104 °C of the pristine lignin. This was due to the fact that the OH groups in the lignin macromers, having low bond-dissociation energy, were replaced by the urethane bonds. In dielectric analysis, the synthesized LigPU exhibited a softening transition at 175 °C corresponding to a combinatorial dual process of the dry Tg,dry of the lignin macromers and the softening of methylenediphenyl urethane chains. This work clearly demonstrated that a high molecular weight of thermoplastic LigPU could be desirably synthesized, broadening the lignin application for value added and eco-friendly products through common melt processes of polymer blend or composites. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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