Blog written by Araceli Galvez Moreno, Project Manager and Senior Researcher at ACCIONA
A composite material is produced by combining several materials and acquires properties far superior to those of its components separately. Specifically, in this post, we refer to thermoset polymers reinforced with glass or carbon fibers (FRP) and which, in our case, are used in the construction sector.
This sector is very committed to the best sustainability of its materials and processes, since up to 30% of the waste generated in the European Union is CDW and 11% of this waste is composite materials1. One of the ways to improve its circularity is the use of waste (secondary raw materials) in its manufacture and the improvement of the material’s recycling processes.
Currently, there are several ways of recycling composite materials:
- mechanical recycling: crushing and grinding with subsequent incorporation into mixtures of different kinds.
- thermochemical recycling: thermal decomposition of the polymer matrix to recover the fibers and energy or some of the chemicals from the polymeric matrix.
- In recent years, a new development of chemical recycling (solvolysis) has been carried out to obtain products with greater added value and for which there is an increasingly strong commitment.
ACCIONA has experience with the mechanical recycling of composite materials. Through crushing and grinding techniques at different sizes, fractions with different applications are obtained, such as the use of the fraction < 200 microns as reinforcement fillers in the manufacture of new composite materials. This process is the simplest, although it requires a control of the granulometry and the final mixture to be able to establish the processing parameters, but it is also the one that most reduces the value of the recycled material.
ACCIONA also has experience in thermochemical recycling, where a thermal decomposition of the polymer in an inert atmosphere results in the production of clean reinforcing fibers for processing in new fabrics, compounding or other applications. This technology adds greater value to the final product, as well as being able to carry out energy and material use due to the decomposition of the polymer matrix.
Finally, the recycling methodology covered in REDOL project is solvolysis (MOSES), where solvents and established temperature and pressure conditions are used to separate the polymer matrix from the reinforcement with the least impact on the latter and with the possibility of obtaining the starting monomers and reagents of the polymer.
The recycling of reinforcing fibers is an essential step to improve the sustainability of composite materials and promote the circularity of their production processes. The improvement in the quality of these fibers will lead to a wider range of applications as it will motivate the substitution of commercial products made with virgin fiber.
Currently, there are companies that sell recycled carbon and glass fiber, mostly from production waste, but they do not process them to make fabrics or continuous fiber giving greater value to the final product. In the REDOL project, AITEX technological center will process recycled fibers to obtain fabrics with which ACCIONA can produce new composite materials.
Throughout REDOL project, progress will be made considering the circular manufacturing of composites as well as other types of materials. The scope of circularity in the production of new materials is a multidisciplinary activity that is still under research and development in many areas and needs the collaboration of different sectors to complete the circle.
If you want to keep up to date with how these developments are progressing, sign up for our newsletter or visit the project website.
Blog written by Araceli Galvez Moreno, Project Manager and Senior Researcher at ACCIONA
