Revealing filler morphology in 3D-printed thermoset nanocomposites by scanning microbeam X-ray scattering
Revealing filler morphology in 3D-printed thermoset nanocomposites by scanning microbeam X-ray scattering
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DOI：
10.1016/j.addma.2020.101729
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发表时间：
2021
影响因子：
11
通讯作者：
E. Trigg;Nadim S Hmeidat;L. Smieska;A. Woll;B. Compton;H. Koerner
中科院分区：
文献类型：
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作者：
E. Trigg;Nadim S Hmeidat;L. Smieska;A. Woll;B. Compton;H. Koerner
环氧树脂-纳米粘土-碳纤维复合材料的常温直写墨水印刷可生产出具有高刚性和高强度的零件。在印刷参数、填充物取向和性能之间建立明确的关系是困难的，部分原因是表征方面的挑战。在这里，我们对(A)环氧-纳米粘土复合材料和(B)环氧-纳米粘土-碳纤维增强复合材料印制件的横截面进行了空间分辨率为5微米的扫描微束X射线散射。纳米粘土的形态被直接可视化，比其他技术更清晰地照亮了道路几何图形。在每条道路的边界附近，纳米粘土片优先与道路边界共面取向。挤出过程中喷嘴内的剪切对齐和沉积时的道路对道路剪切是导致这种取向的两个被提出的因素。在含有碳纤维的样品中，广角X射线衍射使纤维能够直接映射和可视化到道路几何形状上。碳纤维对纳米粘土的形貌没有显著影响。最后，从小角X射线散射图上定性地再现了偏振光学显微镜图像，揭示了光学显微镜能够可视化这些环氧纳米粘土体系中的大尺度道路结构。
Room temperature direct-ink-write printing of epoxy-nanoclay-carbon fiber composites produces parts with high stiffness and strength. Establishing clear relationships between print parameters, filler orientation, and properties is difficult, in part owing to challenges in characterization. Here, we perform scanning microbeam X-ray scattering with 5 micrometer spatial resolution on cross-sections of printed parts with (a) epoxy-nanoclay composite and (b) epoxy-nanoclay-carbon fiber reinforced composite. The nanoclay morphology is directly visualized, illuminating the road geometry with far greater clarity than other techniques. Near the boundary of each road, the nanoclay platelets are preferentially oriented coplanar with the road boundary. Shear alignment within the nozzle during extrusion, and road-to-road shear upon deposition are two proposed factors leading to this orientation. In the sample containing carbon fiber, wide angle X-ray diffraction enables the mapping and visualization of the fibers directly onto the road geometry. The carbon fiber does not significantly affect the nanoclay morphology. Finally, from the small angle X-ray scattering map, we qualitatively reproduce a polarized optical microscope image, revealing that optical microscopy is capable of visualizing the large-scale road structure in these epoxy-nanoclay systems.