Böcherer David, Montazeri Ramin, Li Yuanyuan, Tisato Silvio, Hambitzer Leonhard, Helmer Dorothea
Department of Microsystems Engineering, University of Freiburg, 79110, Freiburg, Germany.
Freiburg Materials Research Center (FMF), University of Freiburg, 79104, Freiburg, Germany.
Adv Sci (Weinh). 2024 Oct;11(39):e2406311. doi: 10.1002/advs.202406311. Epub 2024 Aug 13.
Lignin, one of the most abundant biomaterials and a large-scale industrial waste product, is a promising filler for polymers as it reduces the amount of fossil resources and is readily available. 3D printing is well-known for producing detailed polymer structures in small sizes at low waste production. Especially light-assisted 3D printing is a powerful technique for production of high-resolution structures. However, lignin acts as a very efficient absorber for UV and visible light limiting the printability of lignin composites, reducing its potential as a high-volume filler. In this work, the decolorization of lignin is presented for high-resolution 3D printing of biocomposites with lignin content up to 40 wt.%. Organosolv lignin (OSL) is decolorized by an optimized low-energy process of acetylation and subsequent UV irradiation reducing the UV absorbance by 71%. By integration of decolorized lignin into bio-based tetrahydrofurfuryl acrylate (THFA), a lignin content of 40 wt.% and a resolution of 250 µm is achieved. Due to the reinforcing properties of lignin, the stiffness and strength of the material is increased by factors of 15 and 2.3, respectively. This work paves the way for the re-use of a large amount of lignin waste for 3D printing of tough materials at high resolution.
木质素是最丰富的生物材料之一，也是一种大规模的工业废品，作为一种有前途的聚合物填料，它减少了化石资源的用量且易于获取。3D打印以在低废品率的情况下生产小尺寸的精细聚合物结构而闻名。特别是光辅助3D打印是一种用于生产高分辨率结构的强大技术。然而，木质素是紫外线和可见光的高效吸收剂，这限制了木质素复合材料的可打印性，降低了其作为大量填料的潜力。在这项工作中，展示了对木质素进行脱色处理，以用于高分辨率3D打印木质素含量高达40 wt.%的生物复合材料。通过优化的低能量乙酰化和随后的紫外线照射过程对有机溶剂木质素（OSL）进行脱色，使其紫外线吸收率降低了71%。通过将脱色后的木质素融入生物基丙烯酸四氢糠酯（THFA）中，实现了40 wt.%的木质素含量和250 µm的分辨率。由于木质素的增强特性，材料的刚度和强度分别提高了15倍和2.3倍。这项工作为大量木质素废料用于高分辨率3D打印坚韧材料的再利用铺平了道路。
