Periodic Reporting for period 1 - SUSPENS (Sustainable structural sandwiches and hollow composites parts for automotive, boat and aerospace markets)
Berichtszeitraum: 2023-01-01 bis 2024-06-30
Composite materials are used for their exceptional mechanical properties in relation to their weight. This allows the transportation sector to design lighter vehicles and reduce the energy needed for our mobility. However, composites also have a significant environment.
SUSPENS ambition is to reduce the environmental footprint of composite structures for the automotive, leisure boat and aerospace industries. To do so, matrices and reinforcing fibers will be developed using bio-based ingredients. Carbon fibers will be produced from lignin and cellulose, which are components of wood. SUSPENS will also design new bio-based epoxy and polyester resins.
Processes for manufacturing complex parts in a single step will be used in order to reduce the energy consumption and eliminate very costly assembly operations.
Finally, SUSPENS will work on an upcycling process to reclaim bio-based resin constituents and reinforcing fibers from end-of-life parts. Both of which will then be reused to produce new parts and therefore close the loop.
SUSPENS ambition is to reduce the environmental footprint of composite structures for the automotive, leisure boat and aerospace industries. To do so, matrices and reinforcing fibers will be developed using bio-based ingredients. Carbon fibers will be produced from lignin and cellulose, which are components of wood. SUSPENS will also design new bio-based epoxy and polyester resins.
Processes for manufacturing complex parts in a single step will be used in order to reduce the energy consumption and eliminate very costly assembly operations.
Finally, SUSPENS will work on an upcycling process to reclaim bio-based resin constituents and reinforcing fibers from end-of-life parts. Both of which will then be reused to produce new parts and therefore close the loop.
As mentioned in the context above, polymer resins used as matrix are highly derived from petrol. ORINEO and the University of Côte d'Azur are developing an epoxy with a very high bio-based content. Megara Resin are focusing on the substitution of Styrene as reactive diluent by a bio-based and non toxic one for the production of a bio-based unsaturated polyester resin system. CentexBel will screen bio-based fire retardant additives capable of meeting standards of the automotive sector.
When it comes to reinforcements, a collaboration between CentexBel and NTUA is working on replacing PAN that is petrol-based with a lignin-Bio Polymer blend.
Aalto University in Finland is also working the performance of cellulose fibres in composite applications with the objective to reach specific properties close to that of E-glass fibers
LIPEX is a German company that designs glass fiber production lines. Their role is demonstrate the technical and economic viability of remelting reclaimed glass fibers to produce new ones.
In collaboration with the TU Dresden as a subcontractor, we will produce a continuous carbon staple yarn from discontinuous CF collected as production waste from aerospace factories.
Regarding part manufacturing using those new ingredients, Jules Verne Institute is working on a composite process that will produce complex hollow structures in one-step and substitute the multiple part assembly process that is the standard today which will reduce energy consumption drastically as only one heating cycle will be required for the whole structure.
Finally, NTUA is working on the demonstration that hot gases collected from carbon fibre production lines can be used to pyrolyse the resin from end-of-life parts and reclaim the carbon fibre without using any extra energy.
M18 progress:
Bio-based Epoxy resin development: More than 30 recipes have been prepared and tested using three different bio-based epoxy bases and three different bio-based hardeners. A shortlist of three recipes containing a bio-based content superior to 90% and giving a glass transition temperature (Tg) above 90°C and a tensile modulus above 2GPa has been selected for further testing. The three formulations have been tested to the evaluate the processing conditions, such as minimum viscosity and gel time. One recipe stands out on these two items and is now being supplied in larger quantities to be processed into composite panels in WP3.
Bio-based UPR resin development: More than 30 recipes have been prepared and tested using ten bio-based monomers. Two formulations have been shortlisted as giving a glass transition temperature superior to 65°C and a tensile modulus superior to 2GPa as requested by the industrial requirements. These formulations have a viscosity sufficiently low to be processed at room temperature. However, the use of styrene could only by reduced by 50% in these two formulations (when the project aims a full replacement). Further work is being carried out to identify a good bio-based substitute.
Bio-based flame retardant: Non-toxic flame-retardant additives have been identified, but their effectiveness in the developed Suspens resins still has to be confirmed as well as the UV and fluid resistance of the resins.
Recycled glass fiber development: LIPEX have started a search for 5kg of clean glass fibre reclaimed from end-of-life boats or wind turbines. They have tested various sources until finding the right one. They have remelted 100% of the recycled glass fiber (project objective is 50%) and have produced a glass fiber out of it. Based on the latest test results, it was decided to continue with this setup for next steps.
Cellulose based fibre: Lyocell-type continuous filaments have been spun via the Ioncell® process using pre-hydrolysed kraft pulp (PHK, 0.5 km, Oct. 2023). Following properties have been achieved: elongation: 13 %; tenacity: 705 MPa; Young`s modulus: 19 GPa; toughness: 57 MPa. The fibers have been successfully delivered to WP3 for testing.
Lignin-based carbon fibre: Lignin-based precursor: Four commercial lignin grades were selected and analysed. Eight biopolymers have been selected for blending with commercial lignin. Based on lab-scale blending trials one type of lignin has been selected.
At pilot-scale, lignin A was compounded with up to 50% of each polymer. The produced compounds were analysed via SEM and TGA. The samples have been sent to NTUA for carbonisation trials.
Carbonisation: Batch process investigations have been performed in a vertical furnace to identify the temperature profile for the fibre stabilization under different stresses. Trials have been performed to identify the best temperature profile without breaking the fibre in the furnace. Optical microscopy, DSC, TGA and FTIR were performed on the samples to investigate the modification of each treatment.
Recycled carbon fibre: Samples have been procured for both production waste and fibres reclaimed using a steam-thermolysis process and sent to TU Dresden for processability assessment. The production waste samples with a cut length of 60-80 mm have been found to be the best candidate. A modification of the spinning line to achieve the highest possible content of carbon is in progress and is due to be operational in M30.
Processing: Test panels have been produced from the reference materials identified in the industrial requirements deliverable. A composite panel has been produced using the cellulose fibre produced by Aalto in WP2. Processing trials of two candidate and a reference UPR resin have been performed by APM. A mould for the aerospace demonstrator has been designed and produced.
Recycling: Simulation activities have been performed in order to allow the most promising design for the novel pyrolysis line implementation. Furthermore, initial pyrolysis trials have been performed to allow the identification of the optimum process parameters, which then will be tailored in the pyrolysis line.
When it comes to reinforcements, a collaboration between CentexBel and NTUA is working on replacing PAN that is petrol-based with a lignin-Bio Polymer blend.
Aalto University in Finland is also working the performance of cellulose fibres in composite applications with the objective to reach specific properties close to that of E-glass fibers
LIPEX is a German company that designs glass fiber production lines. Their role is demonstrate the technical and economic viability of remelting reclaimed glass fibers to produce new ones.
In collaboration with the TU Dresden as a subcontractor, we will produce a continuous carbon staple yarn from discontinuous CF collected as production waste from aerospace factories.
Regarding part manufacturing using those new ingredients, Jules Verne Institute is working on a composite process that will produce complex hollow structures in one-step and substitute the multiple part assembly process that is the standard today which will reduce energy consumption drastically as only one heating cycle will be required for the whole structure.
Finally, NTUA is working on the demonstration that hot gases collected from carbon fibre production lines can be used to pyrolyse the resin from end-of-life parts and reclaim the carbon fibre without using any extra energy.
M18 progress:
Bio-based Epoxy resin development: More than 30 recipes have been prepared and tested using three different bio-based epoxy bases and three different bio-based hardeners. A shortlist of three recipes containing a bio-based content superior to 90% and giving a glass transition temperature (Tg) above 90°C and a tensile modulus above 2GPa has been selected for further testing. The three formulations have been tested to the evaluate the processing conditions, such as minimum viscosity and gel time. One recipe stands out on these two items and is now being supplied in larger quantities to be processed into composite panels in WP3.
Bio-based UPR resin development: More than 30 recipes have been prepared and tested using ten bio-based monomers. Two formulations have been shortlisted as giving a glass transition temperature superior to 65°C and a tensile modulus superior to 2GPa as requested by the industrial requirements. These formulations have a viscosity sufficiently low to be processed at room temperature. However, the use of styrene could only by reduced by 50% in these two formulations (when the project aims a full replacement). Further work is being carried out to identify a good bio-based substitute.
Bio-based flame retardant: Non-toxic flame-retardant additives have been identified, but their effectiveness in the developed Suspens resins still has to be confirmed as well as the UV and fluid resistance of the resins.
Recycled glass fiber development: LIPEX have started a search for 5kg of clean glass fibre reclaimed from end-of-life boats or wind turbines. They have tested various sources until finding the right one. They have remelted 100% of the recycled glass fiber (project objective is 50%) and have produced a glass fiber out of it. Based on the latest test results, it was decided to continue with this setup for next steps.
Cellulose based fibre: Lyocell-type continuous filaments have been spun via the Ioncell® process using pre-hydrolysed kraft pulp (PHK, 0.5 km, Oct. 2023). Following properties have been achieved: elongation: 13 %; tenacity: 705 MPa; Young`s modulus: 19 GPa; toughness: 57 MPa. The fibers have been successfully delivered to WP3 for testing.
Lignin-based carbon fibre: Lignin-based precursor: Four commercial lignin grades were selected and analysed. Eight biopolymers have been selected for blending with commercial lignin. Based on lab-scale blending trials one type of lignin has been selected.
At pilot-scale, lignin A was compounded with up to 50% of each polymer. The produced compounds were analysed via SEM and TGA. The samples have been sent to NTUA for carbonisation trials.
Carbonisation: Batch process investigations have been performed in a vertical furnace to identify the temperature profile for the fibre stabilization under different stresses. Trials have been performed to identify the best temperature profile without breaking the fibre in the furnace. Optical microscopy, DSC, TGA and FTIR were performed on the samples to investigate the modification of each treatment.
Recycled carbon fibre: Samples have been procured for both production waste and fibres reclaimed using a steam-thermolysis process and sent to TU Dresden for processability assessment. The production waste samples with a cut length of 60-80 mm have been found to be the best candidate. A modification of the spinning line to achieve the highest possible content of carbon is in progress and is due to be operational in M30.
Processing: Test panels have been produced from the reference materials identified in the industrial requirements deliverable. A composite panel has been produced using the cellulose fibre produced by Aalto in WP2. Processing trials of two candidate and a reference UPR resin have been performed by APM. A mould for the aerospace demonstrator has been designed and produced.
Recycling: Simulation activities have been performed in order to allow the most promising design for the novel pyrolysis line implementation. Furthermore, initial pyrolysis trials have been performed to allow the identification of the optimum process parameters, which then will be tailored in the pyrolysis line.
Bio-based ingredients are too difficult to procure and do not exist at industrial scale, nor competitive costs.