Cellulose Nanocrystal-enabled Manufacturing of Carbon Nanotube/Carbon fiber Polymer Composites

复合材料系统是通过将增强材料混合和粘结到基质中来实现所需的性能，如轻质和高强度。将碳纤维和碳纳米管等增强材料加入到聚合物基质中的加工方法有很多，但由于分散性差和粘附性差，大多数加工方法的性能低于预期。这项研究建立了一种新的制造工艺，基于纤维素纳米晶，将原始纳米材料集成到聚合物基质中，而不需要广泛的化学或加工努力。新工艺能够以更少的加工步骤大规模生产具有所需结构和性能的纳米结构杂化聚合物基复合材料，从而实现这些结构的经济制造，并对美国航空航天、汽车、海洋和国防工业产生影响。这项研究是一项跨学科的努力，涉及加工与制造科学、材料科学和化学，为美国劳动力培养下一代高技能工程师，并为STEM领域的女性和代表性不足的少数群体提供独特的研究机会。碳纳米管(CNTs)和碳纤维(CFs)由于其优异的性能，已被广泛应用于聚合物基复合材料(PMC)中的纳米结构。在PMCs中集成碳纳米管/碳纤维的合成和加工技术有很多种。然而，这些技术普遍面临着一些障碍，如分散性差，界面和层间结合弱，缺乏对结构形成的控制，缺乏可扩展性。特别是，目前对纳米尺度相互作用缺乏了解，缺乏定制这些相互作用的能力，减缓了具有可定制性能的混合纳米结构PMC的制造速度。该项目旨在通过提供关于纳米结构如何通过分子水平的相互作用形成纳米结构以及它们如何转化为纳米结构混合PMC中的界面结合和层间强度的基本理解来填补这一知识空白。在这项研究中产生的新知识导致了一门新的加工科学，其中辅助纳米材料，即纤维素纳米晶(CNCS)，被用来利用杂化复合材料的结构，而不需要昂贵和耗时的加工。该研究团队进行密度泛函理论和分子动力学计算，并结合实验光谱和表征，以测试CNCS决定分子相互作用的假设，并确定纳米结构CNT/CF聚合物复合材料在微观和介观尺度上的微结构形成。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Composite material systems are manufactured by mixing and binding reinforcement materials into a matrix to realize desirable properties such as lightweight and high strength. There are many processing methods to incorporate reinforcement materials, such as carbon fibers and carbon nanotubes, into polymer matrices but most result in lower-than-expected properties due to poor dispersion and weak adhesion. This research establishes a new manufacturing process, based on cellulose nanocrystals, that integrates pristine nanomaterials into the polymer matrix without the need for extensive chemical or processing efforts. The new process enables the production of nanostructured hybrid polymer matrix composites at large scale with desired structure and performance with fewer processing steps, leading to economic manufacturing of these structures with impact to the U.S. aerospace, automotive, marine and defense industries. This research is an interdisciplinary effort that involves processing and manufacturing science, materials science, and chemistry and trains the next generation of highly skilled engineers for the U.S. workforce and provides unique research opportunities for women and underrepresented minority groups in STEM fields. Owing to their superior properties, carbon nanotubes (CNTs) and carbon fibers (CFs) have been extensively used to create nanostructures in polymer matrix composites (PMCs). There are various synthesis and processing techniques to integrate CNTs/CFs in PMCs. However, these techniques generally face a number of hurdles such as poor dispersion, weak interfacial and interlayer adhesion, lack of control on structure formation and lack of scalability. Particularly, the current lack of understanding in nanoscale interactions and lack of capability to tailor these interactions have decelerated manufacturing of hybrid nanostructured PMCs with tailorable performance. This project aims to fill this knowledge gap by providing fundamental understanding of how nanostructures are formed from molecular-level interactions and how they are translated into interfacial bonding and interlaminar strength in nanostructured hybrid PMCs. The new knowledge generated in this research leads to a new processing science where assisting nanomaterials, i.e. cellulose nanocrystals (CNCs), are employed to harness the architecture of hybrid composites without the need for costly and time-consuming processing. The research team performs density functional theory and molecular dynamics calculations in conjunction with experimental spectroscopy and characterization to test the hypothesis that CNCs dictate the molecular interactions and determine the formation of microstructure at micro- and meso-scales in nanostructured CNT/CF polymer composites.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.