Modelling, processing and characterization of carbon nanotube polymer composites

为了实现下一代航空航天结构材料，必须研究新的先进材料形式。碳纳米管（CNT）在1991年被发现时，被认为是纳米复合材料的理想增强材料。近十年来，碳纳米管的合成、性能和应用研究为碳纳米管聚合物纳米复合材料的性能研究带来了巨大的价值。大多数早期的工作都集中在将纳米管作为增强剂直接掺入树脂中。结果表明，通过溶液浇铸、熔体混合、熔融纤维、原位聚合和纳米管功能化处理得到的热塑性和热固性聚合物纳米复合材料的性能存在显著差异。这主要是由于碳纳米管体积分数大于1%时，用聚合物基体加工碳纳米管的难度很大。导致这些令人失望的结果的主要原因是纳米管的分散、排列和与聚合物基体的界面控制不佳。综上所述，该研究计划的目标是开发和实施一个集成框架，包括建模、加工和表征，以生产用于宏观规模和微机电系统（MEMS）应用的高性能碳纳米管聚合物纳米复合材料。将开发新的模型来预测碳纳米管聚合物纳米复合材料的物理、力学和加工性能，这些性能是纳米管分散、浓度、纯化、功能化和取向的函数。将建立碳纳米管聚合物纳米复合材料、混合复合材料层压板和MEMS微致动器的创新制造技术。由于碳纳米管纳米复合材料的研究大多集中在制备和测试上，而没有考虑到加工问题，因此集成方法是一种新的方法。这项工作可能有助于开发新的纳米复合材料制造技术，将利用碳纳米管作为增强材料的全部潜力。

To achieve the next generation of aerospace structural materials, new advanced material forms must be investigated. At the time of their discovery in 1991, carbon nanotubes (CNT) were believed to be the ideal reinforcements for nanocomposites. Over the last decade, the research on carbon nanotubes synthesis, properties and applications have produced a massive amount of values for the properties of CNT polymer nanocomposites. Most of the earlier work focused on the direct incorporation of the nanotubes as reinforcements in the resin. The results show significant variability in properties obtained for thermoplastic and thermoset polymer nanocomposites processed by solution casting, melt mixing, melt fibres, in-situ polymerization and nanotube functionalization. This is mainly caused by the great difficulty of processing CNT with polymer matrices at CNT volume fraction greater than one percent. Issues with the poor control of the nanotube dispersion, alignment and interface with the polymer matrix are principally responsible for these disappointing results. In light of the above, the objective of the proposed research program is to develop and implement an integrated framework that includes modelling, processing and characterization in order to produce high performance CNT polymer nanocomposites for macro scale and microelectromechanical systems (MEMS) applications. New models that predict the physical, mechanical and processing properties of CNT polymer nanocomposites as a function of nanotube dispersion, concentration, purification, functionalization and orientation will be developed. Innovative manufacturing techniques to produce CNT polymer nanocomposites, hybrid composite laminates and MEMS microactuators will be established. The integration approach is new as most efforts on CNT nanocomposite development focused on making and testing the nanocomposite without taking processing issues into account. The proposed work could help develop new nanocomposite manufacturing techniques that will use the full potential of CNT as reinforcements.