Vitrimer matrix composites for space application
Topic(s) : Special Sessions
Co-authors :
Joséphine DE CALBIAC (FRANCE), Marina TORRES , Marion BROUTELLE (FRANCE), Mathias DESTARAC (FRANCE), Rima SFAR ZBED (FRANCE), Marc GUERRE , Philippe OLIVIER (FRANCE)Abstract :
Introduction:
Carbon fiber-reinforced polymer composites in space structures are widely used for their low weight and high thermal stability. However, industrial manufacturing can introduce dimensional deformities or discontinuities. These defects are challenging to correct, especially in a cross-linked thermoset material, as its chemical structure is fixed and not reprocessable. Vitrimers, that combine the attributes of thermoset and thermoplastic materials, offer a viable alternative to classical thermoset matrix. Thanks to the thermo-reversibility of the dynamic elements embedded within the cross-linked network, these matrices exhibit thermoset behavior at the application temperature and glass-like fluidity at higher temperatures, with macroscopic flow occurring above the glass transition due to chemical rearrangement.
This specific feature is expected to enable unprecedented reparability, reshape, and weldability for a thermoset material. Numerous studies have already been published on matrix of Tg in the range of 80-150°C (1,2), but gradually, research is extending to high-performance applications involving high-strength composite materials and, consequently, resilient resins with high glass transition temperature.
Results:
In this work, a space-grade epoxy thermoset matrix has been converted into a high Tg vitrimer matrix (Tg = 200°C) for prospective use in composites. The dynamic chemistry involves disulfide exchanges, with use of industrially available reagents (4-AFD). Reactivity and rheology tests are conducted to ensure that the cross-linking kinetics in the presence of dynamic cross-linking agents are compatible with existing manufacturing processes of composites. These measurements enable the construction of Time-Temperature-Transformation (TTT) diagrams, providing precise monitoring of polymerization processes. Several concentration ratios are explored and compared to enhance both the curing process and vitrimeric properties. Relaxation tests reveal a rapid relaxation time (25 s at 230°C), showing the vitrimeric nature of the resin. Non-stoichiometric ratios between epoxy and amine functions (epoxy / amine 1:1,2) exhibit effective reshape and reparability, highlighting their potential as matrices in composites, presenting a competitive alternative to conventional thermosets.
Furthermore, introducing dynamism within the crosslinked network of the matrix may affect the space qualification of the initial thermoset resin. Tests are conducted to verify that dynamic disulfide bonds aren’t compromising outgassing and temperature cycling performance.
Carbon fiber-reinforced polymer composites in space structures are widely used for their low weight and high thermal stability. However, industrial manufacturing can introduce dimensional deformities or discontinuities. These defects are challenging to correct, especially in a cross-linked thermoset material, as its chemical structure is fixed and not reprocessable. Vitrimers, that combine the attributes of thermoset and thermoplastic materials, offer a viable alternative to classical thermoset matrix. Thanks to the thermo-reversibility of the dynamic elements embedded within the cross-linked network, these matrices exhibit thermoset behavior at the application temperature and glass-like fluidity at higher temperatures, with macroscopic flow occurring above the glass transition due to chemical rearrangement.
This specific feature is expected to enable unprecedented reparability, reshape, and weldability for a thermoset material. Numerous studies have already been published on matrix of Tg in the range of 80-150°C (1,2), but gradually, research is extending to high-performance applications involving high-strength composite materials and, consequently, resilient resins with high glass transition temperature.
Results:
In this work, a space-grade epoxy thermoset matrix has been converted into a high Tg vitrimer matrix (Tg = 200°C) for prospective use in composites. The dynamic chemistry involves disulfide exchanges, with use of industrially available reagents (4-AFD). Reactivity and rheology tests are conducted to ensure that the cross-linking kinetics in the presence of dynamic cross-linking agents are compatible with existing manufacturing processes of composites. These measurements enable the construction of Time-Temperature-Transformation (TTT) diagrams, providing precise monitoring of polymerization processes. Several concentration ratios are explored and compared to enhance both the curing process and vitrimeric properties. Relaxation tests reveal a rapid relaxation time (25 s at 230°C), showing the vitrimeric nature of the resin. Non-stoichiometric ratios between epoxy and amine functions (epoxy / amine 1:1,2) exhibit effective reshape and reparability, highlighting their potential as matrices in composites, presenting a competitive alternative to conventional thermosets.
Furthermore, introducing dynamism within the crosslinked network of the matrix may affect the space qualification of the initial thermoset resin. Tests are conducted to verify that dynamic disulfide bonds aren’t compromising outgassing and temperature cycling performance.