HUN-REN-BME Research Group





Development of recyclable-by-design high performance fibre reinforced polymer composites

Project ID:
K 142517
Supported by:
Hungarian National Research, Development and Innovation Office (NKFIH)
Term:
1 October 2022 - 30 September 2026
Supervisor (BME):
Prof. Dr. Andrea Toldy

Participant researchers (BME):
Zsófia Kovács
Dr. Ákos Pomázi
Prof. Dr. Andrea Toldy

Project summary

At present, there are no technologies available for the large-scale material recycling of fibre reinforced thermoset composites. Therefore, this proposal focuses on the development of recyclable-by-design high performance fibre reinforced polymer composites. In particular, two main development directions are envisaged: development of high performance vitrimer based recyclable and repairable carbon fibre reinforced composites and development of high performance flame retarded all-polyamide composite by thermoplastic resin moulding. As for the first direction, the aim is to develop novel vitrimer-based, recyclable and repairable thermoset polymers with tunable topology freezing transition temperature, suitable for high-temperature composite applications, and to elaborate an industrially feasible recycling method that provide recycled matrices and fibre in the same or similar quality to the benchmark composite materials. Furthermore, deeper understanding of structure-property relationships, recycling and repairing mechanisms of vitrimers is foreseen. Concerning the second direction, the aim is to develop self-reinforced, recyclable, in situ polymerised polyamide 6 composites and enable their used in high temperature application areas by flame retardant coatings appropriate for productive and reproducible in-mould coating. The proposal aims to accomplish not only the recycling of the composites but also the reuse of the obtained components, their characterisation including the effect of repeatedly recycled flame retardant additives on the fire performance of composites made from recycled materials.

Project results

Section 1
1 October 2022 - 30 September 2023
During the first year of the project, we reviewed the relevant literature, with a particular focus on the recycling of polymer composites and polymer matrices suitable for recycling in the material. Reference epoxy resins, flame retardant additives (acting in solid and gas phase), vitrimer, caprolactam and coating raw materials, carbon fibre and polyamide 6 reinforcing materials were selected and procured, and the physical and mechanical properties of the raw materials were tested. The manufacturing technology of vitrimers and their carbon fibre composites was developed. Reference self-reinforced polyamide 6 composites were prepared by in-situ polymerisation of caprolactam and flame retarded caprolactam-based polyamide 6 composititons were developed for flame retardant coatings. Differential scanning calorimetric (DSC), thermoanalytical (TGA) and combustibility (oxygen index (LOI), UL-94 standard, pyrolysis flow and Cone calorimetry) tests were used to determine the optimal combination of solid and gas phase flame retardants in the coating. Data collection has been carried out to create an artificial intelligence-based algorithm that can predict the results of large-scale combustion tests of coatings based on the results of structure and small-scale tests, thus making it suitable for preliminary screening of the designed compositions. In the first year, the results were published in two impact factor publications and one in Hungarian, and presented at the European Meeting on Fire Retardant Polymeric Materials (FRPM23), Dübendorf, Switzerland, 26-29.06.2023; International Conference on Composite Materials (ICCM23), Belfast, Northern Ireland, 30.07-04.08.2023. Student involvement resulted in undergraduate theses, BSc and MSc diploma theses.
Production of flame retarded caprolactam-based polyamide 6

Section 2
1 October 2023 - 30 September 2024
In the second year of the project, the vitrimers were flame retarded with phosphorus amines produced by a proprietary process and two commercially available solid and gas phase additives. Then, their fire performance, glass transition temperature, static and dynamic mechanical, morphological properties were investigated. Fibre reinforced reference and flame retarded vitrimer composites were fabricated in the first year using an optimised technology, whereby prepregs were first created and then the composite was produced by hot-pressing. Based on the mechanical and flammability results of the composites, structure-property relationships were determined and the flame retardant mechanisms were analysed in detail. A caprolactam-based flame retardant coating was applied to self-reinforced polyamide 6 composites by in-mould coating, and the mechanical and flammability properties of the coated composite and the adhesion between composite and coating were investigated. We determined the maximum amount of flame retardants and their combinations that do not yet affect the polymerisation reaction or limit the use of the polymer composite. An artificial intelligence-based algorithm for the prediction of the flammability of fibre-reinforced composites has been developed, with particular emphasis on the effect of fibre content on flammability. In the second year, 5 impact factor publications, 3 Hungarian publications and a conference proceeding was published and the results were presented at the International Conference on Eco-Friendly Additives and Materials (ECOFRAM 2024), Valencia, Spain, 22-23.05.2024 and the European Conference on Composite Materials (ECCM21), Nantes, France, 02-05.07.2024. Student involvement resulted in undergraduate theses, BSc and MSc diploma theses. A research progress report was prepared.
All-polyamide composite with flame retardant coating

Section 3
1 October 2024 - 30 September 2025

Section 4
1 October 2025 - 30 September 2026



Project-related publications


  1. Kovács Zs., Toldy A.: Synergistic flame retardant coatings for carbon fibre-reinforced polyamide 6 composites based on expandable graphite, red phosphorus, and magnesium oxide. Polymer Degradation and Stability, 222, 110696/1-110696/ (2024) 10.1016/j.polymdegradstab.2024.110696 IF=6.3 D1
  2. Kovács Zs., Toldy A.: Flame retardant coatings for E-caprolactam-based self-reinforced polyamide 6 composites. in 'ECCM21 – 21st European Conference on Composite Materials Nantes, Franciaország. 2024.07.02.-05.,989-995 (2024)
  3. Gere D., Pomázi F., Szöllősi A., Jahanpeyma P., Ermilov A. A., Baranya S., Toldy A.: Mikroműanyag szennyezés vizsgálata a Duna budapesti szakaszán. Polimerek, 2, 66-72 (2024)
  4. Kovács Zs., Toldy A.: Flame retardancy via in-mould coating and durability of flame retardants after mechanical recycling in all-polyamide composites prepared by in situ polymerisation. Macromolecular Materials and Engineering, , 202400325/1-202400325/11 (2024) 10.1002/mame.202400325 IF=4.2 Q2
  5. Toldy A., Poór D. I., Szolnoki B., Devecser B., Geier N., Pomázi Á.: Comparative study of flame retardancy in polyimine vitrimers and composites: Evaluating additive and reactive flame retardants acting via gas-, solid-, and combined-phase mechanisms. Journal of Materials Science & Technology, 196, 101-111 (2024) 10.1016/j.jmst.2024.01.047 IF=11.2 D1
  6. Pomázi Á., Poór D. I., Geier N., Toldy A.: Optimising Recycling Processes for Polyimine-Based Vitrimer Carbon Fibre-Reinforced Composites: A Comparative Study on Reinforcement Recovery and Material Properties. Materials, 17(10), 2372/1-2372/15 (2024) 10.3390/ma17102372 IF=3.1 Q1
  7. Poór Dániel István, Tobey Marina, Taynton Philip, Pomázi Ákos, Toldy Andrea, Geier Norbert: A comparative machinability analysis of polyimine vitrimer, epoxy and polycarbonate polymers through orthogonal machining experiments. International Journal of Advanced Manufacturing Technology, , s00170-024-13087-9/1-s00170-024-13087-9/16 (2024) 10.1007/s00170-024-13087-9 IF=2.9 Q2
  8. Kovács Zs., Toldy A.: Development of flame retardant coatings containing hexaphenoxycyclotriphosphazene and expandable graphite for carbon fibre-reinforced polyamide 6 composites. Polymer Degradation and Stability, 230, 111017 (2024) 10.1016/j.polymdegradstab.2024.111017 IF=6.3 D1
  9. Kovács Zs., Pomázi Á., Toldy A.: Development of multifunctional flame-retardant gel coatings for automotive applications. Coatings, 13 (2), 345/1-345/14 (2023) 10.3390/coatings13020345 IF=2.9 Q2
  10. Kovács Zs., Pomázi Á., Hollósi E., Toldy A.: ε-kaprolaktám alapú égésgátló bevonat fejlesztése szénszál erősítésű poliamid 6 kompozitokhoz. Polimerek, 3, 90-96 (2023)
  11. Zielinski D., Szpecht A., Pomázi Á., Kovács Zs., Szolnoki B., Pinke B., Toldy A., Smiglak M.: Multifunctional modifying systems based on ionic liquids for epoxy resin systems and composites. Applied Sciences-Basel, 13, 10661/1-10661/ (2023) 10.3390/app131910661 IF=2.5 Q1

© 2014 BME Department of Polymer Engineering - Created by: Dr. Romhány Gábor