Hui Zhao, Haonan Zhang, Hao Ren, Huamin Zhai
Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Jiangsu Provincial Key Lab of Pulp and Paper Science and Technology, Nanjing Forestry University, Nanjing 210037, China.
Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Jiangsu Provincial Key Lab of Pulp and Paper Science and Technology, Nanjing Forestry University, Nanjing 210037, China.
Int J Biol Macromol. 2022 Jun 1;209(Pt A):1465-1476. doi: 10.1016/j.ijbiomac.2022.04.127. Epub 2022 Apr 22.
Spruce kraft lignin (SKL) has received considerable attention in recent years for its application in the field of polymer materials. However, its structural complexity and polydispersity pose significant challenges for commercial applications. In this study, molecular structure models of acetone soluble kraft lignin (ASKL) and acetone insoluble kraft lignin (AIKL) were proposed based on quantitative calculations of the connection mode of functional groups and structural units. The lignin was modified by quaternization and synthesized in situ as lignin/ZnO composites. Based on the detailed characterization of the micromorphology and structure of the composites, waterborne polyurethane (WPU) films were optimally prepared using 0.6 wt% of the composites. The results showed that the composite films prepared from ASKL have the best UV-blocking performance and mechanical properties. The highest UVA and UVB blocking rates were 98% and 100%, respectively, and the highest tensile strength and elongation at break were 31.2 MPa and 732%, respectively. The differences in the structure and functional groups of the different types of SKL were accurately identified. ASKL is advantageous for the development of UV-blocking films because of its low molecular weight and the presence of abundant phenolic hydroxyl groups, which facilitate the formation of hydrogen bonds, improve the compatibility, and ensure uniform dispersibility. The results of this study are of practical importance in the field of nano-functional materials for the high-value application of industrial lignin.
近年来，云杉硫酸盐木质素（SKL）因其在高分子材料领域的应用而备受关注。然而，其结构复杂性和多分散性给商业应用带来了重大挑战。在本研究中，基于官能团与结构单元连接方式的定量计算，提出了丙酮可溶硫酸盐木质素（ASKL）和丙酮不溶硫酸盐木质素（AIKL）的分子结构模型。通过季铵化对木质素进行改性，并原位合成木质素/ZnO复合材料。基于对复合材料微观形态和结构的详细表征，使用0.6 wt%的复合材料优化制备了水性聚氨酯（WPU）薄膜。结果表明，由ASKL制备的复合薄膜具有最佳的紫外线阻隔性能和力学性能。UVA和UVB的最高阻隔率分别为98%和100%，最高拉伸强度和断裂伸长率分别为31.2 MPa和732%。准确识别了不同类型SKL在结构和官能团上的差异。ASKL因其分子量低且存在大量酚羟基，有利于氢键的形成，提高了相容性并确保了均匀分散性，从而有利于制备紫外线阻隔薄膜。本研究结果对于工业木质素在纳米功能材料领域的高值化应用具有实际意义。
