Naseri Iman, Yourdkhani Mostafa
Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado80523, United States.
School of Advanced Materials Discovery, Colorado State University, Fort Collins, Colorado80523, United States.
ACS Appl Mater Interfaces. 2022 Oct 13. doi: 10.1021/acsami.2c15415.
Current technologies for the manufacture of fiber-reinforced polymer composites are energy-intensive, environmentally unfriendly, and time-consuming and require expensive equipment and resources. In addition, composites typically lack key nonstructural functionalities (e.g., electrical conductivity for deicing, lightning strike protection, and structural health monitoring), which are crucial to many applications such as aerospace and wind energy. Here, we present a new approach for rapid and energy-efficient manufacturing of multifunctional composites without using traditional expensive autoclaves, ovens, or heated molds used for curing of composites. Our approach is predicated on embedding a thin conductive nanostructured paper in the composite layup to act as a resistive heater for triggering frontal polymerization of the matrix thermosetting resin of the composite laminate. Upon passing electric current, the nanostructured paper quickly heats up and initiates frontal polymerization, which then rapidly propagates through the thickness of the laminate, resulting in rapid curing of composites (within seconds to few minutes) irrespective of the size of the composite laminate. The integrated nanostructured paper remains advantageous during the service of the composite part by imparting new functionalities (e.g., deicing) to the cured composite, owing to its excellent electrical conductivity and electrothermal properties. In this work, we first study the influence of several composite processing parameters on the electrothermal properties of the nanostructured paper and determine the power required for rapid initiation of frontal polymerization. We then successfully fabricate a 10 cm × 10 cm composite panel within 1 min using only 4.49 kJ of energy, which is 4 orders of magnitude less than the energy consumed by the traditional bulk, oven-curing technique. Detailed experiments are conducted to provide an in-depth understanding of the effect of heater position, tooling material, and input power on frontal curing of composite laminates. The multifunctional response of produced composites is demonstrated by performing a deicing experiment, where a 50 × 50 × 3 mm cube of ice is completely melted within 3 min using an input power of 77 W.
目前用于制造纤维增强聚合物复合材料的技术能源密集、不环保且耗时，还需要昂贵的设备和资源。此外，复合材料通常缺乏关键的非结构功能（例如用于除冰、雷击防护和结构健康监测的导电性），而这些功能对于航空航天和风能等许多应用至关重要。在此，我们提出了一种新方法，可快速且节能地制造多功能复合材料，无需使用用于复合材料固化的传统昂贵高压釜、烤箱或加热模具。我们的方法基于在复合材料叠层中嵌入一张薄的导电纳米结构纸，作为电阻加热器来引发复合层压板基体热固性树脂的前沿聚合反应。通过电流时，纳米结构纸迅速升温并引发前沿聚合反应，然后该反应迅速在层压板厚度方向上传播，从而使复合材料快速固化（在几秒到几分钟内），而与复合层压板的尺寸无关。由于其优异的导电性和电热性能，集成的纳米结构纸在复合部件服役期间仍具有优势，可为固化后的复合材料赋予新功能（例如除冰）。在这项工作中，我们首先研究了几个复合材料加工参数对纳米结构纸电热性能的影响，并确定了快速引发前沿聚合反应所需的功率。然后，我们仅使用4.49千焦的能量在1分钟内成功制造出一块10厘米×10厘米的复合板，这比传统的批量烤箱固化技术消耗的能量少4个数量级。我们进行了详细的实验，以深入了解加热器位置、模具材料和输入功率对复合层压板前沿固化的影响。通过进行除冰实验证明了所制备复合材料的多功能响应，在该实验中，一块50×50×3毫米的冰块在输入功率77瓦的情况下3分钟内完全融化。
