Quantitative Chemical Analysis Throughout the FC CVD Process as a Route to Reliable Fibre Production and Research
View / Open Files
Authors
Ryley, James
Advisors
O'Neill, Bill
Date
2020-10-28Awarding Institution
University of Cambridge
Qualification
Doctor of Philosophy (PhD)
Type
Thesis
Metadata
Show full item recordCitation
Ryley, J. (2020). Quantitative Chemical Analysis Throughout the FC CVD Process as a Route to Reliable Fibre Production and Research (Doctoral thesis). https://doi.org/10.17863/CAM.82016
Abstract
Carbon nanotube fibre production through the Floating Catalyst – Chemical Vapour Deposition (FC-CVD) process has been developed at Cambridge University for 14 years by the Macromolecular Materials Laboratory (MML) group. Since then research has focused on lab-scale processes and fibre property optimisation. Continued research has been stymied by unreliable reactor performance and repeatability. Investigations were therefore undertaken to expand instrumentation and process control capabilities on the reactor, and furthermore to investigate the reaction mechanics of the process in order to deepen our understanding and enable further improvement of fibre properties.
Improved process control has been achieved through a Fourier-Transformed Infra-Red spectrometer integrated into the gas line to monitor the precursor feedstocks in real time. This has revealed the erratic and inaccurate behaviour of precursor delivery, held as responsible for the reactor’s poor performance up to this point. Precursor delivery reliability has now been greatly improved but can more importantly be corrected for live when making fibre, which has enabled the publication of a major study into predicting fibre properties [1].
Further work, sampling reactor furnace gases at four positions (the first time this has been reported), has produced novel insight into the gas chemistry of the FC-CVD process. While ferrocene and thiophene precursors decomposed too rapidly to study, contributing only small quantities of common gases, hydrocarbon and alcohol precursors produced a variety of chemical species that varied with reaction parameters of dispensing quantity and hydrogen flow rate. Furnace gases from toluene in particular showed significant quantities of benzene deep in the laminar flow zone, and reduced levels of methane, ethene and acetylene, which were further lowered when higher flow rates carried more intact benzene deeper into the furnace. This effect and other observations about gaseous precursor products have been related to MML publications with conclusions drawn about CNT reaction mechanisms.
Keywords
Carbon Nanotubes, CNT, Floating Catalyst Chemical Vapour Deposition, FCCVD, Infra-red Spectroscopy, FTIR, Gas Analysis
Sponsorship
EPSRC (1645503)
Identifiers
This record's DOI: https://doi.org/10.17863/CAM.82016
Statistics
Total file downloads (since January 2020). For more information on metrics see the
IRUS guide.
Recommended or similar items
The current recommendation prototype on the Apollo Repository will be turned off on 03 February 2023. Although the pilot has been fruitful for both parties, the service provider IKVA is focusing on horizon scanning products and so the recommender service can no longer be supported. We recognise the importance of recommender services in supporting research discovery and are evaluating offerings from other service providers. If you would like to offer feedback on this decision please contact us on: support@repository.cam.ac.uk