High Molecular-Weight Thermoplastic Polymerization of Kraft Lignin Macromers with Diisocyanate

BioResources

Nguyen Dang Luong¹  Seong-Hoon Lee¹  Joon-Suk Oh¹  Le Dai Duong²  Ju-Ho Yun³  Gi-Yong Nam⁴  Ho-Kyu Yoon⁴  In-Kyung Park⁴  Chong-Gu Lee⁵  Jae-Do Nam⁶  Youngkwan Lee⁷  Suk-Ho Hwang⁸ 

[1] Korea;Department of Energy Science, Sungkyunkwan University;Department of Materials Science and Engineering, Korea University, Seoul, South Korea;Department of Polymer Science and Engineering, Sungkyunkwan University, Suwon, South Korea;Hyundai Motors Company, Hwaseong, South Korea;Korea Automotive Technology Institute, Chonan, South Korea;Polymer Technology, Department of Biotechnology and Chemical Technology, Aalto University, School of Chemical Technology, P.O. Box 16100, 00076 Aalto, Finland;School of Chemical Engineering, Sungkyunkwan University, Suwon, South Korea;

关键词: Lignin;    Lignin-based polyurethane;    Eco-friendly;    Dielectric analysis;    Glass transition temperature;   

DOI  :  10.15376/biores.9.2.2359-2371

来源: DOAJ

【 摘 要 】

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.

【 授权许可】

Unknown