Additive-Free and Support-Free 3D Printing of Thermosetting Polymers with Isotropic Mechanical Properties
Additive-Free and Support-Free 3D Printing of Thermosetting Polymers with Isotropic Mechanical Properties
复制标题
DOI：
10.1021/acsami.0c19608
复制
发表时间：
2021-01-21
影响因子：
9.5
通讯作者：
Minary-Jolandan, Majid
中科院分区：
文献类型：
--
作者：
Mahmoudi, Mohammadreza;Burlison, Scott R.;Minary-Jolandan, Majid
热塑性3D打印的民主化源于经济的熔化和成型使加工变得容易。另一方面，热固性聚合物没有享受到这种优势，因为热固性树脂在没有交联或过量填料的情况下不能保持其形状，并且一旦交联，它们就不能被挤出用于印刷。由于这一艰巨的挑战，到目前为止，热固性聚合物的3D打印仅限于专用光敏树脂的光聚合或负载大部分（高达20重量%）流变改性剂的树脂的挤出。在这里，我们报告了一种用于纯商业环氧聚合物的3D打印的无流变改性剂和光引发剂的工艺，没有任何树脂改性并使用传统的3D打印机。一种低成本的非牛顿支撑材料，在喷嘴剪切应力下在固体-流体状态之间切换，能够打印复杂的3D结构和随后的“一步”固化。我们的研究结果表明，一步固化消除了逐层3D打印过程中常见的层间粘附力，并产生了前所未有的各向同性机械性能（强度，弹性模量，拉伸韧性和失效应变）。这种用于热固性聚合物的浴内打印和固化（IBPC）3D打印工艺成本低、可扩展、高速（喷嘴速度超过720 cm/min）和高分辨率（低至220 μ m的细丝尺寸）。我们展示了业余爱好者，结构和航空航天部件，纤维增强复合材料等的潜在应用。
The democratization of thermoplastic 3D printing is rooted in the ease of processing enabled by economical melting and shaping. Thermosetting polymers, on the other hand, have not enjoyed this advantage given that thermosetting resins cannot hold their shape without cross-linking or excessive fillers, and once cross-linked, they cannot be extruded for printing. Due to this formidable challenge, thus far, 3D printing of thermosetting polymers has been limited to the photopolymerization of specialized photosensitive resins or extrusion of resins loaded with large fractions (as high as 20 wt %) of rheology modifiers. Here, we report a rheology-modifier- and photoinitiator-free process for the 3D printing of a pure commercial epoxy polymer, without any resin modification and using a conventional 3D printer. A low-cost non-Newtonian support material that switches between solid-fluid states under a nozzle shear stress enables the printing of complex 3D structures and the subsequent and "one-step" curing. Our results show that the one-step curing eliminates the often-compromised interlayer adhesion common in layer-by-layer 3D printing processes and results in unprecedented isotropic mechanical properties (strength, elastic modulus, tensile toughness, and strain to failure). This in-bath print and cure (IBPC) 3D printing process for thermosetting polymers is low-cost, scalable, high-speed (nozzle speeds exceeding 720 cm/min), and high-resolution (down to 220 mu m filament size). We demonstrate potential applications for hobbyists, structural and aerospace components, and fiber-reinforced composites, among others.