Large-scale solvent-free functionalisation of carbon nanotubes

Lead Research Organisation: Imperial College London
Department Name: Dept of Chemistry

Abstract

Due to their unique properties, carbon nanotubes are critical enabling materials in a wide range of applications, ranging from advanced polymer composites, to battery electrodes. They are already produced in tonne quantities and the market is growing rapidly. However, in order to optimise their processing and performance it is necessary to modify their surface chemically. Current chemical techniques are slow, wasteful, and typically operate at a small scale; they are fundamentally ill-suited to the industrial production of CVD nanotubes where plant capacity is often on the order of 100 tonnes pa. We have developed a versatile, rapid, and clean approach to nanotube modification that we believe to be inherently scalable and compatible with existing nanotube production facilities. The proposed project will demonstrate this scalability and provide samples of modified nanotubes with a range of value-adding properties. These examples will be selected both to satisfy the requirements of existing nanotube users, and to stimulate new markets that depend on larger volumes of modified nanotubes than are currently available. With this proof-of-concept data in place, our patented technology will be exploited in order to create a new generation of nanotube-based products.
 
Description Due to their unique properties, carbon nanotubes are critical enabling materials in a wide range of applications, ranging from advanced polymer composites, to battery electrodes. They are already produced in tonne quantities and the market is growing rapidly. However, in order to optimise their processing and performance it is necessary to modify their surface chemically. Current chemical techniques are slow, wasteful, and typically operate at a small scale; they are fundamentally ill-suited to the industrial production of CVD nanotubes where plant capacity is often on the order of 100 tonnes pa. We have developed a versatile, rapid, and clean approach to nanotube modification that we believe to be inherently scalable and compatible with existing nanotube production facilities. The project demonstrated this scalability and provided samples of modified nanotubes with a range of value-adding properties. These examples were selected both to satisfy the requirements of existing nanotube users, and to stimulate new markets that depend on larger volumes of modified nanotubes than are currently available. With this proof-of-concept data in place, our patented technology will be exploited in order to create a new generation of nanotube-based products.


The project demonstrated a range of practical features critical to commercial exploitation. Most importantly, the process scale was increased from the original 100mg to 5g. At this largest scale, thermal transfer issues became significant, but can be readily tackled in the next phase of development using fluidised bed processes available at commercial partners. In addition, the central thermal activation process was shown to operate under a nitrogen atmosphere as well as under vacuum, and to be effective using the native nanotube oxides available after synthesis (avoiding an explicit oxidation step). Pure gas phase modification, purification, and work-up were further demonstrated. Studies of the activation process and mechanism suggest methods to manipulate the degree of functionalisation effected, and provide a rationale for selecting modification agents in future.

In discussion with commercial partners, several key targets for potential high value products were selected and achieved. Most importantly, the process was extended from multi-walled nanotubes to single-wall nanotubes with an unexpected degree of success. A range of commercially-relevant modifications were also undertaken, and shown to be effective in improving dispersibility in selected solvents, and improving composite performance. These results were essential in order to stimulate exploitation through licensing arrangements.
Exploitation Route The basic methodology has proved applicable to a wide range of nanocarbons, including nanotubes, graphene nanoplatelets, and carbon blacks, and is straightforward for others to use. We have exploited the approach extensively for the preparation of aqueous suspensions, and applied them in a range of biological studies with collaborators in the UK and US. These same dispersions may also be considered technological inks relevant to applications including electrodes, composites, filters, catalyst supports and so on.
Sectors Aerospace, Defence and Marine,Chemicals,Electronics,Energy,Pharmaceuticals and Medical Biotechnology,Transport

 
Description The process was licensed to a commercial chemicals company, and explored as a route to producing functionalised materials.
First Year Of Impact 2012
Sector Chemicals,Manufacturing, including Industrial Biotechology
Impact Types Economic

 
Description Leverhulme Trust
Amount £238,749 (GBP)
Funding ID F/07 058/BT 
Organisation The Leverhulme Trust 
Sector Charity/Non Profit
Country United Kingdom
Start 10/2011 
End 09/2014
 
Description Leverhulme Trust
Amount £238,749 (GBP)
Funding ID F/07 058/BT 
Organisation The Leverhulme Trust 
Sector Charity/Non Profit
Country United Kingdom
Start 10/2011 
End 04/2014
 
Description NIEHS
Amount £268,500 (GBP)
Funding ID 1U19ES019536-01 
Organisation National Institute of Environmental Health Sciences 
Sector Public
Country United States
Start 05/2010 
End 05/2015
 
Description NIEHS
Amount £268,500 (GBP)
Funding ID 1U19ES019536-01 
Organisation National Institute of Environmental Health Sciences 
Sector Public
Country United States
Start 04/2011 
End 04/2016
 
Description Thomas Swan and Co Ltd 
Organisation Thomas Swan and Co Ltd
Country United Kingdom 
Sector Private 
PI Contribution Long standing partnership developing technology and licensing it
Collaborator Contribution Development of synthesis and processing routes relevant to new company products. Advice and discussion. CASE studentships (3)
Impact New nanomaterials products.
 
Title Process for the production of a functionalised carbon nanomaterial 
Description Gas phase functionalisation of nanocarbons 
IP Reference US2011245384 
Protection Patent granted
Year Protection Granted 2011
Licensed Yes
Impact Lead to year long secondment from the company.