Three-dimensional (3D) printing is extensively explored in scientific research and engineering applications; however, little is known about the feasibility of 3D printing multi-material composites. This paper investigates the effect of three different plasticizers including epoxidized soybean oil (ESO), polyethylene glycol (PEG), and glycerol on mechanical and thermal properties of PLA filled with distillers dried grains with solubles (DDGS) filaments for 3D printing. The composite filaments were extruded using a twin-screw extruder equipped with a collector to achieve uniform diameter. The eco-friendly PLA-DDGS-plasticizer based filaments were then used to print dog-bone and flexural samples. The results showed that the PLA-DDGS blends plasticized with ESO have improved elongation at break compared to pure PLA and those plasticized with glycerol and PEG. These results were evidenced by SEM micrographs showing PLA-plasticizers phase separations and formation of voids in fracture surface of PLA-DDGS plasticized by PEG and glycerol. DMA and FT-IR measurements confirmed the compatibility between PLA and ESO. PLA-DDGS blend containing 10 % ESO exhibited 6 % higher storage modulus in comparison with PLA samples, while the addition of 12.5 % ESO reduced storage modulus by 27 %. Storage modulus in 3D printed samples plasticized by PEG and glycerol showed a reduction of 32 % and 89 %, respectively. The same trend was observed in the mechanical properties of 3D printed composite filaments. Among all samples, PLA-DDGS blends plasticized by 15 % ESO exhibited higher elongation at the break while a significant reduction of 21 % was observed in ultimate tensile strength. The study confirmed that the types and amounts of plasticizer dictates the morphology and mechanical properties of PLA-DDGS composite.

三维（3D）打印在科学研究和工程应用中得到了广泛的探索；然而，人们对 3D 打印多材料复合材料的可行性知之甚少。本文研究了包括环氧化大豆油 (ESO)、聚乙二醇 (PEG) 和甘油在内的三种不同增塑剂对 3D 打印用可溶物干酒糟 (DDGS) 长丝填充的 PLA 的机械和热性能的影响。使用配备收集器的双螺杆挤出机挤出复合长丝以获得均匀的直径。然后使用环保型 PLA-DDGS 增塑剂长丝打印狗骨和弯曲样品。结果表明，与纯 PLA 和用甘油和 PEG 增塑的那些相比，用 ESO 增塑的 PLA-DDGS 共混物具有更高的断裂伸长率。这些结果由 SEM 显微照片证明，显示 PLA-增塑剂相分离并在由 PEG 和甘油增塑的 PLA-DDGS 的断裂表面形成空隙。DMA 和 FT-IR 测量证实了 PLA 和 ESO 之间的兼容性。与 PLA 样品相比，含有 10% ESO 的 PLA-DDGS 混合物表现出高 6% 的储能模量，而添加 12.5% ESO 使储能模量降低 27%。PEG 和甘油增塑的 3D 打印样品的储能模量分别降低了 32% 和 89%。在 3D 打印复合长丝的机械性能中观察到了相同的趋势。在所有样本中，用 15% ESO 增塑的 PLA-DDGS 混合物表现出更高的断裂伸长率，同时观察到极限拉伸强度显着降低了 21%。研究证实，增塑剂的类型和用量决定了 PLA-DDGS 复合材料的形态和机械性能。