Department of Polymer Engineering , University of Akron , Akron , Ohio 44325 , United States.
Departments of Materials Engineering and Mechanical Engineering , Purdue University , West Lafayette , Indiana 47907 , United States.
ACS Appl Mater Interfaces. 2018 May 9;10(18):16087-16094. doi: 10.1021/acsami.8b00866. Epub 2018 Apr 26.
Net-shape manufacture of customizable objects through three-dimensional (3D) printing offers tremendous promise for personalization to improve the fit, performance, and comfort associated with devices and tools used in our daily lives. However, the application of 3D printing in structural objects has been limited by their poor mechanical performance that manifests from the layer-by-layer process by which the part is produced. Here, this interfacial weakness is overcome using a structured, core-shell polymer filament where a polycarbonate (PC) core solidifies quickly to define the shape, whereas an olefin ionomer shell contains functionality (crystallinity and ionic) that strengthen the interface between the printed layers. This structured filament leads to improved dimensional accuracy and impact resistance in comparison to the individual components. The impact resistance from structured filaments containing 45 vol % shell can exceed 800 J/m. The origins of this improved impact resistance are probed using X-ray microcomputed tomography. Energy is dissipated by delamination of the shell from PC near the crack tip, whereas PC remains intact to provide stability to the part after impact. This structured filament provides tremendous improvements in the critical properties for manufacture and represents a major leap forward in the impact properties obtainable for 3D-printed parts.
通过三维（3D）打印实现定制对象的净成型为个性化提供了巨大的潜力，可提高与我们日常生活中使用的设备和工具相关的贴合度、性能和舒适度。然而，3D 打印在结构物体中的应用受到其较差的机械性能的限制，这种性能表现在零件生产的逐层工艺中。在这里，通过使用结构化的核壳聚合物长丝克服了这种界面弱点，其中聚碳酸酯（PC）芯部快速固化以定义形状，而烯烃离聚物壳部含有增强打印层之间界面的功能（结晶度和离子性）。与单个组件相比，这种结构化长丝可提高尺寸精度和抗冲击性。含有 45 体积%壳部的结构化长丝的抗冲击性可超过 800 J/m。使用 X 射线微计算机断层扫描技术探究了这种改善的抗冲击性的起源。能量通过壳部从靠近裂纹尖端的 PC 分层耗散，而 PC 在冲击后保持完整，为零件提供稳定性。这种结构化长丝在制造的关键性能方面提供了巨大的改进，代表了 3D 打印零件可获得的冲击性能的重大飞跃。
