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

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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.