Abstract Fused-filament fabrication (FFF) is an extrusion-based form of three-dimensional (3D) printing for manufacturing parts rapidly. Commercially available polypropylene (PP) filaments produce shrinkage and warpage, termed dimensional instabilities, or have poor mechanical properties. FFF can therefore only produce prototypes. Polypropylene is a promising material, considering its 3D printed mechanical properties are as high as those from traditional manufacturing, yet, still exhibiting dimensional instabilities. In this work, we solve this instability problem by reinforcing PP with microcapsules. These microcapsules comprise polylactic acid (PLA) and reduced graphene oxide, confirmed by x-ray diffraction, x-ray photoelectron spectroscopy and Raman spectroscopy. By first encapsulating graphene with PLA, once melt-compounded, our scanning and transmitting electron microscopy shows that the PLA-graphene microcapsules are well dispersed throughout the PP main matrix. Our rheological analysis shows that our PP nanocomposites exhibit high melt elasticity, giving better support to printing constructs, and low viscosity, promoting printability, avoiding nozzle clogging and filament buckling. At 30% volume fraction, our nanocomposites also outperform the neat PP in mechanical testing.

中文翻译：

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用石墨烯-聚乳酸微胶囊增强聚丙烯用于熔丝制造

摘要 熔丝制造 (FFF) 是一种基于挤出的三维 (3D) 打印形式，用于快速制造零件。市售聚丙烯 (PP) 长丝会产生收缩和翘曲，称为尺寸不稳定性，或者机械性能较差。因此，FFF 只能生产原型。聚丙烯是一种很有前途的材料，考虑到其 3D 打印的机械性能与传统制造的机械性能一样高，但仍表现出尺寸不稳定性。在这项工作中，我们通过用微胶囊增强 PP 来解决这个不稳定性问题。这些微胶囊包含聚乳酸 (PLA) 和还原氧化石墨烯，经 X 射线衍射、X 射线光电子能谱和拉曼光谱证实。首先用 PLA 封装石墨烯，一旦熔融复合，我们的扫描和透射电子显微镜显示 PLA-石墨烯微胶囊很好地分散在整个 PP 主基质中。我们的流变分析表明，我们的 PP 纳米复合材料具有高熔体弹性，为印刷结构提供更好的支持，而低粘度，可提高印刷适性，避免喷嘴堵塞和灯丝屈曲。在 30% 的体积分数下，我们的纳米复合材料在机械测试中也优于纯 PP。