RenFuel K2B Materials AB, Rapsgatan 25, 754 50 Uppsala, Sweden.
Department of Organic Chemistry, Stockholm University, Svante Arrhenius Väg 16C, 106 91 Stockholm, Sweden.
Molecules. 2021 May 27;26(11):3219. doi: 10.3390/molecules26113219.
Lignin is an abundant polymeric renewable material and thus a promising candidate for incorporation in various commercial thermoplastic polymers. One challenge is to increase the dispersibility of amphiphilic lignin in lipophilic thermoplastic polymers We altered Kraft lignin using widely available and renewable fatty acids, such as oleic acid, yielding more than 8 kg of lignin ester as a light brown powder. SEC showed a molecular weight of 5.8 kDa with a PDI = 3.80, while the T of the lignin ester was concluded to 70 °C. Furthermore, the lignin ester was incorporated (20%) into PLA, HDPE, and PP to establish the thermal and mechanical behavior of the blends. DSC and rheological measurements suggest that the lignin ester blends consist of a phase-separated system. The results demonstrate how esterification of lignin allows dispersion in all the evaluated thermoplastic polymers maintaining, to a large extent, the tensile properties of the original material. The impact strength of HDPE and PLA blends show substantial loss upon the addition of the lignin ester. Reconverting the acetic acid side stream into acetic anhydride and reusing the catalyst, the presented methodology can be scaled up to produce a lignin-based substitute to fossil materials.
木质素是一种丰富的聚合物可再生材料，因此是一种很有前途的候选材料，可以纳入各种商业热塑性聚合物中。一个挑战是提高两亲木质素在亲脂性热塑性聚合物中的分散性。我们使用广泛可用和可再生的脂肪酸（如油酸）对 Kraft 木质素进行了改性，得到了超过 8 公斤的浅黄色木质素酯粉末。SEC 显示分子量为 5.8 kDa，PDI=3.80，而木质素酯的 T 则推断为 70°C。此外，木质素酯（20%）被掺入 PLA、HDPE 和 PP 中，以确定共混物的热性能和力学性能。DSC 和流变学测量表明，木质素酯共混物由相分离系统组成。结果表明，木质素的酯化允许其在所有评估的热塑性聚合物中分散，在很大程度上保持了原始材料的拉伸性能。在添加木质素酯后，HDPE 和 PLA 共混物的冲击强度显著降低。通过将乙酸副产物再转化为乙酸酐并重新使用催化剂，该方法可以扩展到生产基于木质素的化石材料替代品。
