Functionalized lignin by grafting phosphorus-nitrogen improves the thermal stability and flame retardancy of polypropylene

Yu, Youming and Fu, Shenyuan and Song, Ping'An and Luo, Xiping and Jin, Yongming and Lu, Fengzhu and Wu, Qiang and Ye, Jiewang (2012) Functionalized lignin by grafting phosphorus-nitrogen improves the thermal stability and flame retardancy of polypropylene. Polymer Degradation and Stability, 97 (4). pp. 541-546. ISSN 0141-3910


Improving the thermal stability and flame retardancy of polymers remains a great challenge. Although lignin has been used as a flame retardant for polymers, its flame retardancy effect is usually limited. We, herein, successfully modified alkali lignin by chemically grafting two flame retardant elements, phosphorous and nitrogen, via a three-step reaction. Compared with lignin, modified lignin (PN-lignin) exhibits a much higher char-forming ability with a char of 61.4 wt% (40.7 wt% for lignin) at 600°C in N 2. PN-lignin confers a much higher thermal stability and amount of char residue on polypropylene relative to lignin. Moreover, PN-lignin further reduces the heat release rate and slows the combustion process, indicating a better flame retardancy. The continuous and intact char layer mainly contributes to the improved flame retardancy. This strategy not only provides a novel method for flame retarding polymeric materials, but greatly extends the comprehensive utilization of industrial lignin.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Files associated with this item cannot be displayed due to copyright restrictions.
Faculty / Department / School: No Faculty
Date Deposited: 30 May 2017 04:42
Last Modified: 30 May 2017 04:42
Uncontrolled Keywords: lignin modification; polypropylene; thermal stability; alkali lignin; char residues; combustion pro-cess; flame retardancy; functionalized; heat release rates; lignin modification; modified lignins; thermodynamics
Fields of Research : 03 Chemical Sciences > 0303 Macromolecular and Materials Chemistry > 030301 Chemical Characterisation of Materials
Socio-Economic Objective: E Expanding Knowledge > 97 Expanding Knowledge > 970103 Expanding Knowledge in the Chemical Sciences
Identification Number or DOI: 10.1016/j.polymdegradstab.2012.01.020

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