Enabling Australia’s Carbon Fibre Industry
It is widely known that the production of polyacrylonitrile (PAN) fibre from the acrylonitrile raw material accounts for ~50% of the carbon fibre production cost and determines ~80% of the final properties. PAN fibre quality is the key to making high quality carbon fibre. Using RAFT polymerisation technology, CSIRO can produce PAN polymers and fibres with high molecular weights and exceptionally well defined structures and properties compared to conventional methods. When converted to carbon fibres, these superior fibres may allow composite manufacturers to use less carbon fibres in their components, improve processing, reduce weight and cost in their final products. The project aim was to put this to the test, utilising industry relevant processing equipment and demonstrate the benefits of making carbon fibre with RAFT-PAN.
The specific objectives were to:
- Demonstrate that the CSIRO technology can be processed on industry relevant equipment to produce carbon fibre
- Quantify the benefits and advantages of using RAFT-PAN materials compared to conventional PAN materials for the production of carbon fibre, and
- Decrease the overall cost of comparable product resulting from manufacturing and product improvement.
The work program consisted of a number of steps:
- Establish a commercial grade baseline carbon fibre, using industry relevant equipment and processing methods, for comparison with the RAFT based carbon fibres
- Establish six different RAFT-PAN formulations for comparison, including polymers with different molecular weight and comonomer compositions
- Produce sufficient amounts of RAFT-PAN (>30 kg in total) to convert into carbon fibre
- Convert the six RAFT-PAN polymers into carbon fibre and test their mechanical properties
- Using the best performing RAFT formulation, produce a composite for mechanical testing.
CSIRO successfully demonstrated that the RAFT-PAN technology could be processed on industry relevant equipment to produce commercial grade carbon fibre. This also demonstrated that the RAFT agents used in the polymer were not detrimental to fibre performance. The highest performing CSIRO carbon fibre was then processed into a composite sheet, utilising aerospace manufacturing methods, for mechanical testing to demonstrate commercial relevance and application.
The benefit in utilising RAFT-PAN in the production of carbon fibre was determined to be negligible when compared to the baseline carbon fibre (using conventional PAN materials) produced during this experimental program. It is possible that the benefits of RAFT-PAN may be less obvious at the lower end of carbon fibre grades, and limitations of the equipment utilised. It is worth noting that although the carbon fibre from RAFT-PAN was produced with no issues it was observed to behave differently through the coagulation process during fibre formation and oxidation during the carbon fibre production process.
The cost benefit model utilised in the analysis resulted in a 10% increase in cost for RAFT-PAN derived carbon fibre composites when compared to the traditional methods. This was due to RAFT carbon fibre not delivering the expected 20% increase in strength. The additional cost is mainly due to the longer reaction time required for the polymerisation process.
Outcome and Impact
The project was not successful in demonstrating that RAFT produced a commercially superior carbon fibre, but the project was successful in demonstrating that the know-how now exists in Australia to produce commercial grade carbon fibre, from molecules to materials. This new knowledge has given CSIRO a unique ability to understand and produce commercial grade carbon fibre, including all the process stages from polymer manufacture to carbon fibre, that can be translated to any PAN fibre technology. CSIRO can assist and offer ongoing support in the establishment of carbon fibre manufacture in Australia as a sovereign capability, producing carbon fibre for Australia’s high tech industries in an environment where high grade carbon
For further information please contact:
Dr Andrew Abbott, CSIRO: firstname.lastname@example.org