Salo Teemu, Di Vito Donato, Halme Aki, Vanhala Jukka
Faculty of Information Technology and Communication Sciences, Tampere University, 33720 Tampere, Finland.
Micromachines (Basel). 2022 Oct 13;13(10):1732. doi: 10.3390/mi13101732.
The addition of fillers has been implemented in fused filament fabrication (FFF), and robust carbon fillers have been found to improve the mechanical, electrical, and thermal properties of 3D-printed matrices. However, in stretchable matrices, the use of fillers imposes significant challenges related to quality and durability. In this work, we show that long carbon staple fibers in the form of permeable carbon fiber cloth (CFC) can be placed into a stretchable thermoplastic polyurethane (TPU) matrix to improve the system. Four CFC sample series (nominally 53−159-µm-thick CFC layers) were prepared with a permeable and compliant thin CFC layer and a highly conductive and stiff thick CFC layer. The sample series was tested with single pull-up tests and cyclic tensile tests with 10,000 cycles and was further studied with digital image correlation (DIC) analyses. The results showed that embedded CFC layers in a TPU matrix can be used for stretchable 3D-printed electronics structures. Samples with a thin 53 µm CFC layer retained electrical properties at 50% cyclic tensile deformations, whereas the samples with a thick >150-µm CFC layer exhibited the lowest resistance (5 Ω/10 mm). Between those structures, the 106-µm-thick CFC layer exhibited balanced electromechanical properties, with resistance changes of 0.5% in the cyclic tests after the orientation of the samples. Furthermore, the suitability of the structure as a sensor was estimated.
在熔融长丝制造（FFF）中已采用添加填料的方法，并且发现坚固的碳填料可改善3D打印基体的机械、电气和热性能。然而，在可拉伸基体中，填料的使用给质量和耐久性带来了重大挑战。在这项工作中，我们表明，可将透气碳纤维布（CFC）形式的长碳短纤维放入可拉伸热塑性聚氨酯（TPU）基体中以改进该系统。制备了四个CFC样品系列（名义厚度为53−159 µm的CFC层），其中包括一个透气且柔顺的薄CFC层和一个高导电性且坚硬的厚CFC层。对该样品系列进行了单次上拉测试和10000次循环的循环拉伸测试，并用数字图像相关（DIC）分析进行了进一步研究。结果表明，TPU基体中嵌入的CFC层可用于可拉伸的3D打印电子结构。具有53 µm薄CFC层的样品在50%循环拉伸变形下仍保持电性能，而具有厚度>150 µm厚CFC层的样品表现出最低电阻（5 Ω/10 mm）。在这些结构之间，106 µm厚的CFC层表现出平衡的机电性能，样品取向后在循环测试中电阻变化为0.5%。此外，还评估了该结构作为传感器的适用性。
