Period: 09/2022 – 08/2025 (36 months)

Funding organization: MCIN/AEI/FEDER

Principal Investigators:

Josep Costa josep.costa@udg.edu (IP 1)

Pere Maimí pere.maimi@udg.edu (IP 2)

Work team:

Daniel Sanchez Rodriguez (AMADE-UdG)

Anbazhagan Subramani (AMADE-UdG)

Funding:

MCIN/AEI/FEDER, “Ajuts a Projectes de Generació de Coneixement” within the framework of the “Programa Estatal per impulsar la Investigació Cientifica-tècnica i la seva transferencia, del Pla Estatal  d’Investigació Científica, Tècnica i d’Innovació 2021-2023” (call 2021) and identifying code MCIN/AEI/10.13039/501100011033; entitled «In search of sustainable, bio-based, hybrid, long-fibre reinforced composites for structural applications»; awarded by resolution on 15.11.2022.

DESCRIPTION

Structural composite materials are currently not recyclable, so a severe environmental problem is generated when components reach their end of life. The possibility of using natural fibers (such as flax or hemp) combined with recyclable matrices would undoubtedly reverse this problem. Indeed, there is currently a strong activity aimed at the development of sustainable matrices (bio-based or not) with self-repair characteristics. However, it is not clear to what extent these raw materials can lead to composite materials suitable to play a structural role in applications in sectors such as automotive or wind turbines.

One stage of the project is aimed at the characterization of recyclable matrices developed by expert institutes in the formulation of polymers. The mechanical behavior of vitrimers and bio-based polymers will be characterized, paying special attention to their toughness and thermal stability, and their viscoelastic behavior in particular. Regarding self-healing properties, there is no consensus as to how to measure them and the disparity of tests with which it is claimed is far from conferring the necessary reliability for the structural design. In order to evaluate the self-healing properties of these formulations, an objective and quantifiable test methodology will be developed with a view to their potential standardization. Said methodology will be applied to the aforementioned vitrimers and bio-based polymers. 

In the second stage of the project, it will be evaluated how the self-healing properties measured in the polymers translate into the ability of the composite material to self-repair the damage mechanisms most related to the matrix: cracking of the matrix in layers at 90 degrees and delaminations generated by out-of-plane loads. Composite materials will be manufactured with the aforementioned recyclable and self-repairing matrices reinforced with fibers of flax or hemp, glass and recycled carbon, and their capacity for self-repair will be evaluated and quantified using experimental methods specifically designed for this purpose.

Finally, hybrid composite materials will be made by combining natural fibers with fiberglass and, on the other hand, natural fibers with recycled carbon fiber. In the first case, glass – natural fibers, a composite material with properties similar to those of a fiberglass composite but with better vibration damping will be pursued. This material points towards applications in wind turbine blades, where to mitigate the resonances is crucial, or in car panels that must combine structural function with the sound isolation of the cabin from outside noise. The natural fiber-recycled carbon hybrid material will be designed to exhibit improved toughness through pseudo-ductile behavior and will target a composite material with performance midway between a fiberglass composite and a carbon composite.

Ultimately, the project will contribute to achieving composite materials with structural capacity, more sustainable, promoting a bio-based economy and facilitating their recycling and the extension of their service life.

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