Recycling composite materials: what are the possibilities of Elium® thermoplastic resins?
Elium® is the first liquid thermoplastic resin that revolutionizes composite materials applications thanks to its recyclability at the end of the product life cycle. Today the thermoplastic resin has been tested for two main recycling technologies: mechanical and chemical processes. We interviewed researchers and engineers at Arkema and Cetim Grand Est research institute to discuss the recycling possibilities with Elium®.
Composite materials have seen growth of 4% a year since 2016, with a ramp-up in thermoplastic composites compared to thermoset composites. But more still needs to be done to manage their end of life. Although a number of factors come into play, the thermoset nature of the resins used to make these materials makes them very hard to recycle.
As a result, most end-of-life composites and production waste go to landfill, because there are no technically or financially viable recycling options, or to cement works for use as solid recovered fuels.
What is Elium® 's potential in the recycling of thermoplastic composite parts?
In a market that is monopolized by thermoset composites, Elium® resin represents an unprecedented innovation. It combines the advantages of a thermoset material with the recyclability of a thermoplastic material. Its potential is huge, particularly as 38,000 tons of composite waste is generated in France each year, out of total production of 380,000 tons.
But although thermoplastic composite materials are profitable to use, the lack of recycling options may constitute an obstacle to their being used on a mass scale. That is why Arkema, alongside its industrial and academic partners, is working on developing recycling in a number of different projects and by creating two different but complementary processes.
Thermoplastic composite mechanical recycling
This is the first realistic industrial solution for recycling thermoplastic composite materials, particularly those made from Elium® resin. To develop it, Arkema is collaborating in the REVEL project with the Grand Est Technical Center for Mechanical Industries (CETIM) and the M2P Technological Research Institute.
According to Clément Callens, BU Manager Industry of the Future & Thermoplastic Processes at CETIM, “the aim is to position the recycling process for composite materials in the light of future applications, and therefore forthcoming industrial projects. To do this, we are evaluating the recyclability by thermomechanical means of production waste or end-of-life parts made from Elium® resin-based composites.”
Parts are crushed and heated and then the material obtained is turned into panels with high mechanical resistance. These recycled composites, which include fibers and resin, can be used in construction and civil engineering, transport, the production of industrial equipment— sectors that are looking for solutions to reduce weight, improve mechanical performance and simplify design.
This solution has the advantage of being adoptable by recycling companies using standard processes, on a small and medium scale, using less energy than complex chemical processes".
Thermoplastic composite chemical recycling
This is the second method for recycling Elium® resin composites. The process consists of crushing the composite and heating it to around 400 degrees in order to turn the solid resin into a gaseous monomer.
“It can be recovered, purified and formulated into a resin that can be used in applications with the same level of performance as the virgin resin”, states Jean-François Devaux, expert research engineer at Arkema. “Chemical recycling also allows operators to take larger volumes, and badly damaged or end-of-life composites do not pose an obstacle to recovering the resin. This means that we can ensure circularity with a material that can be reused for multiple applications.” Recovered carbon or glass fibers can also be recycled, but for applications other than the original use.
Chemical recycling also allows operators to take larger volumes, and damaged composites do not pose an obstacle to recovering the resin. We can ensure circularity with a material that can be reused for multiple applications".
Partnerships are the key driver for composite recycling innovation
In order to put these two recycling methods on a viable industrial footing, Arkema is working closely with its partners. The “REVEL” mechanical recycling project is at an advanced stage, with the development by CETIM Grand Est of its Thermosaïc® technological solution for recycling Elium® resin-based composites.
Meanwhile, there have been several large-scale collaborations in chemical recycling, such as the MMAtwo project on the recycling of PMMA and, soon, Elium® composites, as well as the ZEBRA* program, which focuses on wind turbine blades
* Zebra: Zero wastE Blade ReseArch – MMATwo inset
SPOTLIGHT: what is the MMAtwo?
MMAtwo is an ambitious project involving manufacturers and academics in creating a large PMMA recycling network. It is funded as part of the Horizon 2020 EU research and innovation plan and comprises thirteen partners from six different countries representing all stages of the PMMA value chain. Arkema is heavily involved in MMAtwo as a PMMA producer, and intends to go even further by coming up with a demonstration model for recycling Elium® resin-based composites. Scheduled for 2022.
Anticipating new composite materials
With end-of-life Elium®-based composites coming onto the market in the next few decades, action is being taken now to prepare for this phase in order to be ready to receive these materials and make the most of them in terms of recycling or reuse.
“While waiting for them to reach the end of their life, we can count on consumables made from Elium®-based composite materials arriving in 2024-2025, with production waste from the manufacturing of boats and wind turbine blades...” says Jean-François Devaux. “These account for 5- 10% of composite materials made, and this waste contains significant volumes of Elium® resin, which we want to recover and reuse”. Hence the importance of demonstrating the feasibility of recycling processes to specialist operators, as well as their financial viability.
