Modelling, processing and characterization of carbon nanotube polymer composites

为了实现下一代航天结构材料，必须研究新的先进材料形式。在1991年发现碳纳米管时，碳纳米管被认为是纳米复合材料的理想增强体。在过去的十年里，对碳纳米管的合成、性质和应用的研究对碳纳米管聚合物纳米复合材料的性能产生了巨大的价值。早期的大部分工作集中在直接将纳米管作为增强体结合到树脂中。结果表明，通过溶液浇注、熔融共混、熔融纤维、原位聚合和纳米管功能化等方法制备的热塑性和热固性聚合物纳米复合材料的性能有显著的变化。这主要是由于在碳纳米管体积分数大于1%的情况下，用聚合物基质制备碳纳米管的难度很大。造成这些令人失望的结果的主要原因是纳米管的分散、排列和与聚合物基质的界面控制不佳。有鉴于此，拟议的研究计划的目标是开发和实施一个包括建模、加工和表征的集成框架，以生产用于宏观规模和微电子机械系统(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，作为纳米管分散、浓缩、提纯、功能化和取向的函数。将建立创新的制造技术，以生产碳纳米管聚合物纳米复合材料、混杂复合材料层板和MEMS微致动器。这种集成方法是新的，因为大多数关于碳纳米管纳米复合材料开发的努力都集中在制造和测试纳米复合材料上，而没有考虑加工问题。这项拟议的工作可能有助于开发新的纳米复合材料制造技术，这种技术将充分利用碳纳米管作为增强体的潜力。

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.