School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, People's Republic of China.
Institute of Chemical Industry of Forest Products, CAF; Key Lab. of Biomass Energy and Material, Jiangsu Province; National Engineering Research Center of Low-Carbon Processing and Utilization of Forest Biomass; Key Lab. of Chemical Engineering of Forest Products, National Forestry and Grassland Administration; Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing, People's Republic of China.
Environ Technol. 2024 May;45(13):2506-2518. doi: 10.1080/09593330.2023.2176792. Epub 2023 Feb 20.
To improve the flame retardancy of phenolic foam from the perspective of sustainable development, it is a feasible way to add bio-based flame retardants into phenolic foam. Lignin has a similar structure to phenol, which provides a possibility to replace part of phenol. In this paper, we prepared a kind of reactive bio-based flame retardant based on enzymatic hydrolyzed lignin, in which side chain was chemically grafted with phosphorus and nitrogen and benzene ring would participate in the phenolic condensation reaction. According to elemental analysis and ICP-OES data, the content of nitrogen and phosphorus in modified lignin (NP-L) increased to 2.95% and 3.55% respectively. Compared with original lignin, the carbon residue rate of NP-L increased from 3.25% to 12.13% because of the presence of flame retardant elements N and P. Then lignin-based flame retardant was used to replace phenol for modifying phenolic foams (NPLPFX). The limited oxygen index (LOI) and compressive strength of phenolic foam were improved effectively by adding modified lignin when the substitution rate was less than 25%. The LOI and compressive strength of the modified phenolic foam with 5% replacement amount (NPLPF5) are 55.6% and 0.24 MPa, which increased by 88% and 60% compared with pure phenolic foam. The cone calorimetric data also showed that NPLPF5 had good flame retardancy, and the peak heat release rate and total heat release were significantly lower than PF. This work suggests a novel green strategy for improving the flame retardancy performance of phenolic foam and promoting the utilization of lignin.
为了从可持续发展的角度提高酚醛泡沫的阻燃性，将生物基阻燃剂添加到酚醛泡沫中是一种可行的方法。木质素的结构与苯酚相似，这为部分替代苯酚提供了可能性。本文制备了一种基于酶解木质素的反应型生物基阻燃剂，其中侧链通过化学键接磷和氮，苯环参与酚醛缩合反应。根据元素分析和 ICP-OES 数据，改性木质素（NP-L）中氮和磷的含量分别增加到 2.95%和 3.55%。与原始木质素相比，由于阻燃元素 N 和 P 的存在，NP-L 的残炭率从 3.25%增加到 12.13%。然后，将木质素基阻燃剂用于替代苯酚来改性酚醛泡沫（NPLPFX）。当取代率小于 25%时，添加改性木质素可有效提高酚醛泡沫的极限氧指数（LOI）和压缩强度。取代量为 5%（NPLPF5）时，改性酚醛泡沫的 LOI 和压缩强度分别为 55.6%和 0.24 MPa，分别比纯酚醛泡沫提高了 88%和 60%。锥形量热法数据也表明，NPLPF5 具有良好的阻燃性能，其峰值热释放速率和总热释放量明显低于 PF。这项工作为提高酚醛泡沫的阻燃性能和促进木质素的利用提供了一种新的绿色策略。
