Xu Jindi, Hu Dongying, Zheng Qi, Meng Qiulu, Li Ning
School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China.
Polymers (Basel). 2022 Mar 8;14(6):1071. doi: 10.3390/polym14061071.
There is increasing interest in furfurylated wood, but the polymerization mechanism between its internal polyfurfuryl alcohol (PFA) and lignin is still uncertain. This paper investigated the distribution of PFA and the feasibility of the polymerization of PFA with lignin in furfurylated balsa wood. The wood first immersed in the furfuryl alcohol (FA) solution followed by in situ polymerization and the distribution of PFA was characterized by Raman, fluorescence microscopy, SEM, and CLSM. Then, the mill wood lignin (MWL) of balsa wood and lignin model molecules were catalytically polymerized with PFA, respectively, studying the mechanism of interaction between PFA and lignin. It was concluded that PFA was mainly deposited in cell corner with high lignin concentration, and additionally partly deposited in wood cell cavity due to high concentration of FA and partial delignification. TGA, FTIR, and NMR analysis showed that the cross-linked network structure generated by the substitution of MWL aromatic ring free position by PFA hydroxymethyl enhanced the thermal stability. New chemical shifts were established between PFA and C/C of lignin model A and C/C of model B, respectively. The above results illustrated that lignin-CH-PFA linkage was created between PFA and lignin in the wood cell wall.
人们对糠醇化木材的兴趣日益浓厚，但其内部的聚糠醇（PFA）与木质素之间的聚合机理仍不明确。本文研究了PFA在糠醇化轻木中的分布情况以及PFA与木质素聚合的可行性。木材先浸入糠醇（FA）溶液中，然后进行原位聚合，通过拉曼光谱、荧光显微镜、扫描电子显微镜和共聚焦激光扫描显微镜对PFA的分布进行表征。接着，分别将轻木的磨木木素（MWL）和木质素模型分子与PFA进行催化聚合，研究PFA与木质素之间的相互作用机理。结果表明，PFA主要沉积在木质素浓度较高的细胞角，此外，由于FA浓度高和部分脱木质素作用，PFA还部分沉积在木材细胞腔中。热重分析（TGA）、傅里叶变换红外光谱（FTIR）和核磁共振（NMR）分析表明，PFA羟甲基取代MWL芳环自由位置所产生的交联网络结构提高了热稳定性。分别在PFA与木质素模型A的C/C以及模型B的C/C之间建立了新的化学位移。上述结果表明，在木材细胞壁中，PFA与木质素之间形成了木质素-CH-PFA键。
