Xiong Shao-Jun, Zhou Si-Jie, Wang Hao-Hui, Wang Han-Min, Yu Shixin, Zheng Lu, Yuan Tong-Qi
Beijing Key Laboratory of Lignocellulosic Chemistry, Beijing Forestry University, Beijing 100083, China.
Tianjin Key Laboratory of pulp and paper, Tianjin University of Science and Technology, Tianjin 300457, China.
Int J Biol Macromol. 2022 Jun 1;209(Pt A):1065-1074. doi: 10.1016/j.ijbiomac.2022.04.065. Epub 2022 Apr 18.
Complex and heterogeneous structures of lignin impede its further conversion and valorization. Herein, three technical lignins (from softwood, hardwood, and grass) were fractionated with acetone solvent to reduce their structural heterogeneity, which were then blended with poly-(butylene adipate-co-terephthalate) (PBAT) to fabricate biodegradable bio-composites. Macromolecular structures of lignins and their effects on the properties of lignin/PBAT composites were thoroughly investigated. Results showed that all fractionated lignin composites displayed better properties. Particularly, the raw and fractionated softwood lignin-based composites exhibited superior performance compared with others. Benefiting from the lower molecular weight, hydroxyl groups, and condensation, acetone fractionated softwood lignin presented the lowest T (115.7 °C), achieving ideal melt miscibility and interfacial interaction between lignin and PBAT. The decreased T of lignin facilitated the lignin dispersion in the matrix and increase the mechanical strength of the composites. Overall, the fractionated technical lignin possessed desirable physical and chemical structure features, conferring composites good miscibility and mechanical properties.
木质素复杂且不均一的结构阻碍了其进一步的转化和高值化利用。在此，三种工业木质素（分别来自软木、硬木和草类）用丙酮溶剂进行分级以降低其结构的不均一性，然后与聚（己二酸丁二醇酯-对苯二甲酸丁二醇酯）（PBAT）共混以制备可生物降解的生物复合材料。对木质素的大分子结构及其对木质素/PBAT复合材料性能的影响进行了深入研究。结果表明，所有分级木质素复合材料均表现出更好的性能。特别是，与其他复合材料相比，基于原始软木木质素和分级软木木质素的复合材料表现出优异的性能。得益于较低的分子量、羟基含量和缩合度，丙酮分级软木木质素的熔点最低（115.7℃），实现了木质素与PBAT之间理想的熔体相容性和界面相互作用。木质素熔点的降低促进了其在基体中的分散，并提高了复合材料的机械强度。总体而言，分级工业木质素具有理想的物理和化学结构特征，赋予复合材料良好的相容性和机械性能。
