Wet-spinning carbon fiber precursor begins in Australia

Commonwealth Scientific and Industrial Research Organisation (CSIRO), an Australian research and development center, reports that it, in collaboration with Deakin University (Waurn Ponds, Australia), has begun lab-scale manufacure of carbon fiber using a wet-spinning process.

Director of CSIRO Future Industries, Dr. Anita Hill, says, “This facility means Australia can carry out research across the whole carbon fiber value chain: from molecules, to polymers, to fiber, to finished composite parts,” Dr Hill said. “Together with Deakin, we’ve created something that could disrupt the entire carbon bre manufacturing industry.”

Derek Buckmaster, director, Carbon Nexus at Deakin University, worked closely with CSIRO to help develop the wet-spinning technology. He answered these questions from CW about the process and what CSIRO has planned for further development.

CW: How is wet-spinning used in the CSIRO process?
DB: The CSIRO/Deakin wet-spinning facility includes a small-scale reactor, polymer drying system, dope preparation system and the wet-spinning line. This means we can take a monomer, polymerize this into a polymer, then dissolve the polymer to form “dope,” and finally spin the dope into precursor fibers. When acrylonitrile monomer is used, this series of process steps are the typical steps which are carried out by the industry to produce PAN [polyacrylonitrile] precursor.

CW: Can you tell me more about what materials are used in the precursor?
DB: The “dope” or dissolved polymer solution, is formed prior to spinning the solution into filaments using the wet-spinning line. The facility is designed to allow the use of various polymers, including PAN, cellulose, lignin and blends of these materials. Various solvent systems can also be used, including DMSO, DMAC, DMF and ionic liquids. One aspect of ongoing research is to investigate the effect of adding nano-fillers such as carbon nanotubes and graphene into the dope prior to spinning.

CW: The press release also says the resulting carbon fiber is “stronger and of a higher quality.” Can you quantify this? Is the CSIRO carbon fiber comparable to another carbon fiber on the market?
DB: One of the collaborative research projects being carried out at the CSIRO/Deakin wet-spinning facility is an investigation into the use of RAFT (reversible addition-fragmentation chain transfer polymerization) technology for precursor production. RAFT is a new polymerization method developed by CSIRO which gives better control over PAN molecular weight and polydispersity. (RAFT can be applied to a wide range of polymers, but we are interested in PAN for this project.) Early results have shown that precursors prepared with RAFT polymerized PAN have higher tensile strength than precursors prepared with regular PAN. These results have also passed through to carbon fibre results, and researchers are currently optimizing the carbonisation process prior to releasing detailed results.

CW: What is the tow count of carbon fiber made via the wet-spinning process?
DB: Initial running of the wet spinning line has been conducted producing 0.5k tow, and we expect to eventually be capable of running up to 3K tow. The spinning line is equipped with two spinnerets and spin-pumps and can perform standard wet-spinning into the coagulation bath as well as air-gap wet spinning. Bi-component spinning will also be possible. The 0.5k tows have been carbonized using the carbon fiber research line at Carbon Nexus, next door to the CSIRO building.

CW: What applications do you expect will be most suitable for this carbon fiber?
DB: Industry partners who have expressed interest in working on collaborative research programs at the wet-spinning facility include companies from the automotive and aerospace industries. The research is at the fundamental level of improving the precursor spinning process, and is not necessarily focused on any specific applications at this stage.

CW: One report about this carbon fiber said the price of carbon fiber drop because of this process. What can you say about how the costs of the wet-spinning process compare to traditional carbon fiber manufacturing costs?
DB: This may have been an optimistic report of another of our collaborative research projects between Deakin University and the University of Queensland into the use of nano-fibrillated cellulose sourced from spinifex grass (a native grass growing across 30% of Australia). With such an abundant feedstock source for potential use in PAN precursor production, there is an expectation of reducing the cost of precursor if the project is successful. However the techno-economic feasibility is yet to be fully investigated. This project will utilize the wet-spinning facility for pilot-scale trials.

CW: How much testing and evaluation of this carbon fiber has been done?
DB: We are in the early days of the facility’s operation, so the first PAN precursor samples from the line have been carbonized within the last few weeks.

CW: Is the CSIRO facility pilot-scale only? If so, what are the plans for commercialization? Will it be licensed to a manufacturer, or does CSIRO intend to achieve scale-up itself?
DB: Yes, the line is a pilot-scale line, installed with the goal of developing and demonstrating technology for licensing. CSIRO and Deakin University do not intend to scale-up the technology themselves, but with industry partners.

CW: Will CSIRO make carbon fiber samples available for customer evaluation?
DB: Yes, CSIRO and Deakin University will make samples available for evaluation by research partners, to enable the scoping of projects. Since the goal of the facility is to carry out research into novel precursor chemistries for wet spinning, we want to work closely with industry partners and other research institutes.

CW: In what forms has CSIRO made this carbon fiber? UD? Woven? Braided? Tows?
DB: Currently we have not created any fabrics from carbon fiber produced from precursor off the wet-spinning line. CSIRO has the ability to carry out weaving, braiding, knittng and prepregging on the same site.

CW: Has CSIRO evaluated any sizing with this carbon fiber?
DB: The precursor fibers which have been carbonized at the Carbon Nexus facility have used standard sizing – off the shelf – from Michelman, our sizing partner. No specific work has commenced into sizing yet, but this is an area where Deakin University carries out a number of research programs.