Abstract Lignin nanoparticles (LNP) were obtained by an acidolysis process from corn pristine lignin. X-ray photoelectron spectroscopy (XPS) and radical scavenging activity (RSA) of the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) confirmed a significant enhancement in reactivity of LNP in comparison with pristine lignin. Polyurethane (PU) nanocomposites were prepared by pre-polymerization of polyethylene glycol and diisocyanates in the presence of different contents (1, 3, 5 and 7 wt%) of LNP. The effects of LNP, serving as both biobased polyol and crosslinker, on the mechanical, hydrophobicity and dielectric behavior of the resulted PU nanocomposites were investigated. Tensile test results showed an overall enhancement for mechanical performance, and the elongation at break exceeded 1000% for all studied PU nanocomposites. Meanwhile, dynamic mechanical analysis (DMA) revealed that the crosslinking densities gradually increased with LNP addition. Furthermore, LNP based PU nanocomposites showed inherent resistance towards ultraviolet radiation and frequency dependent behavior for electrical conductivity. On the other hand, LNP based PU nanocomposites revealed good thermal reprocessability due to the transcarbamoylation reaction in the presence of DBTDL catalyst.

中文翻译：

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具有良好再加工性的疏水、抗紫外线和介电聚氨酯-纳米木质素复合材料

摘要 木质素纳米颗粒 (LNP) 是通过酸解过程从玉米原始木质素中获得的。X 射线光电子能谱 (XPS) 和自由基 2,2-二苯基-1-苦基肼 (DPPH) 的自由基清除活性 (RSA) 证实，与原始木质素相比，LNP 的反应性显着增强。聚氨酯 (PU) 纳米复合材料是通过聚乙二醇和二异氰酸酯在不同含量 (1、3、5 和 7 wt%) 的 LNP 存在下进行预聚合制备的。研究了作为生物基多元醇和交联剂的 LNP 对所得 PU 纳米复合材料的机械、疏水性和介电性能的影响。拉伸试验结果表明，所有研究的 PU 纳米复合材料的机械性能都有整体提高，断裂伸长率超过 1000%。同时，动态力学分析（DMA）表明，随着 LNP 的加入，交联密度逐渐增加。此外，基于 LNP 的 PU 纳米复合材料显示出对紫外线辐射的固有抵抗力和电导率的频率相关行为。另一方面，由于在 DBTDL 催化剂存在下的氨基甲酰化反应，基于 LNP 的 PU 纳米复合材料显示出良好的热可再加工性。