| On April 17, 2018, it was learned from foreign media that a research group at Western Reserve University in Cleveland recently studied a group of interesting 3D printing New materials, these materials may have many useful applications. The project was jointly completed by Prof. Rigoberto Advincula and Qiqi Chen and Peng-Fei Cao of the Department of Polymer Science and Engineering. Their work was in an article called 'Mechanically Robust'. In the paper by Ultraelastic Hierarchical Foam with Tunable Properties via 3D Printing', published in the magazine Advanced Functional Materials. The team uses Viscous Solution Printing (VSP). 3D printing technology (also known as Ink-Writing (DIW)) to make super-elastic foam.  The direct print function using digital 3D models can generate complex structures with high precision, enabling engineers to control the porosity on a microscopic and macroscale scale. This research uses polyurethane, a common plastic material. 3D printing can make The structure of the material is controlled at different levels so that it is porous, thereby significantly improving the required properties. 3D printing offers a higher level of complexity in the final structure of the foam compared to the molding or casting methods. . VSP 3D printing technology utilizes a syringe to extrude viscous ink material onto a build plate, setting it in place to create a 3D structure layer by layer. This 3D printing technology has advantages over conventional FDM extrusion methods because it can be used more Kinds of materials for printing. These include metals, hydrogels and aerogels, as well as ceramics and thermoplastics. The ink used in 3D printing technology is a thixotropic material, which means it is not smooth and can be deformed under external stress. These inks are prepared by a simple one-pot process in which double nanoparticles (nanoclay and silica Nanoparticles are dispersed in a polyurethane suspension. Precise control of ink viscosity, as well as syringe design, printing parameters and 3D design itself, all allow for ultimate control of the final 3D printed structure. Thermoplastic Polyurethane (TPU) is manufactured with a graded porous structure. At the macroscopic scale, by Placed in the original 3D design to create larger holes in the structure. In the next stage, when the object is immersed in water, large micropores are created by the post-print phase separation process. The smallest microholes are created by chemical etching. The resulting TPU foam structures are lightweight and exhibit good mechanical strength. They also have unprecedented elasticity, more than 1,000 compression cycles, and excellent sturdiness, quickly after being over 20,000 times their own weight. restore. The mechanical properties of superelastic foams can be adjusted according to the application they are used for. The same is true for their conductive properties. As a demonstration, a small sponge made of foam is immersed in a solution of carbon nanotubes (CNT) in water. As van de Waal The strength of the carbon nanotubes grips the surface of the TPU foam. After drying, the foam is applied to the circuit board and used as a highly sensitive resistive resistivity sensor. This is actually a flexible power switch that can compress it. To turn the circuit on or off. In addition to flexible electronics, this printable 3D printable TPU foam can also be used to improve many other existing applications for polyurethanes, including footwear (such as New Balance's 3D printing trainer). Car seats, packaging and tissue engineering Scaffolding The ink mixture can also be changed to obtain similar effects to plastics other than polyurethane. |
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