Han Gaojie, Zhou Bing, Li Zhaoyang, Feng Yuezhan, Liu Chuntai, Shen Changyu
State Key Laboratory of Structural Analysis, Optimization and CAE Software for Industrial Equipment, National Engineering Research Center for Advanced Polymer Processing Technology, Zhengzhou University, Zhengzhou 450002, China.
Mater Horiz. 2023 Jul 31;10(8):3051-3060. doi: 10.1039/d3mh00600j.
Aramid nanofibers (ANFs) with a nanoscale diameter, large aspect ratio, and exposed electronegative surface, as well as ultrahigh thermal/chemical inertness and extreme mechanical properties, provide promising applications in many emerging fields, but these are greatly limited by the low preparation efficiency and broad diameter distribution. Herein, we put forward a high-efficiency wet ball milling-assisted deprotonation (BMAD) strategy to rapidly prepare ANFs with an ultrafine diameter. The strong shear and collision forces from ball-milling induced stripping and splitting effects on the macroscopic fibers, which promoted the penetration and expanded the contact interfaces between reactants, thus accelerating the deprotonation reaction and refining the ANF diameter. As a result, ultrafine ANFs with a diameter of only 2.09 nm and high concentration (1 wt%) were successfully achieved within 30 min. This BMAD strategy represents a vastly advantageous approach compared to the existing reported ANF preparation approaches in terms of efficiency (20 g L h) and fiber diameter. The ultrafine microstructure leads to the corresponding ANF nanopaper having more compact stacking and fewer defects, thus exhibiting extraordinary mechanical properties including tensile strength (271.7 MPa) and toughness (33.1 MJ m). This work achieves significant progress toward high-efficiency production of ultrafine ANFs, bringing about appreciable prospects in preparing promising multifunctional ANF-based materials.
芳纶纳米纤维（ANFs）具有纳米级直径、大长径比和暴露的负电表面，以及超高的热/化学惰性和优异的机械性能，在许多新兴领域具有广阔的应用前景，但这些应用受到低制备效率和宽直径分布的极大限制。在此，我们提出了一种高效的湿球磨辅助去质子化（BMAD）策略，以快速制备具有超细直径的ANFs。球磨产生的强大剪切力和碰撞力对宏观纤维产生剥离和分裂作用，促进了反应物的渗透并扩大了接触界面，从而加速了去质子化反应并细化了ANF直径。结果，在30分钟内成功制备出直径仅为2.09 nm且浓度高（1 wt%）的超细ANFs。与现有的报道的ANF制备方法相比，这种BMAD策略在效率（20 g L h）和纤维直径方面具有极大的优势。超细微观结构导致相应的ANF纳米纸具有更紧密的堆积和更少的缺陷，从而表现出非凡的机械性能，包括拉伸强度（271.7 MPa）和韧性（33.1 MJ m）。这项工作在高效生产超细ANFs方面取得了重大进展，为制备有前景的多功能ANF基材料带来了可观的前景。
