Nowadays over 60% of thermoset composite waste ends in landfills or incinerated, and this makes this type of material one of the biggest challenges for the waste treatment industry. Only in the aeronautical industry, 700 aircraft with composite parts are reaching the end of their operational lives every year. In this sense, the use of composite materials has gained interest in recent years due to their unique properties such as high mechanical strength, corrosion resistance, lightness, and long durability. These materials can be found in many applications. Dor this reason, new lines of research try to seek for innovative solutions to demonstrate new technologies for recycling composites.
As success stories, Aitiip coordinates two different European projects in line with these objectives. VIBES project presents a solution based on a combination of novel biobased bonding products and a chemical debonding technology. In this way, initiating the degradation of the thermoset composite components can be triggered under controlled external stimuli. The final decomposition of the original resin into selective monomers-polymers takes place with the help of a biobased organic solvent inside a controlled reactor.
BIZENTE project presents an innovative solution based on the development of a new technology focused on the controlled biodegradation of these materials by means of the use of ligninase enzymes. Instead of using a chemical solvent, enzymes are trained via an evolution approach, forcing them to present a high appetite for targeted functional groups. The technologies developed in these projects can decrease the amount of biobased or non-biobased thermoset plastics currently burnt or landfilled by at least 40%.
Recover high value components
One of the main goals is to valorise high value components such as fibres. The technologies developed within these two projects allow the recovery of high-quality fibres and resins without irreversible damage. The composites based on the combination of resins such as epoxy, polyester and vinylester with different type of fibres such as carbon, biobased carbon, glass, and flax fibres, are the largest category of composites currently used by industry worldwide. These types of composites are precisely the ones addressed by BIZENTE and VIBES solutions to enable their recyclability.
As a result of both processes, the fibres are not soluble in green solvents or attacked by enzymes, so they are easily recovered by filtration and characterised to understand their physicochemical properties for further valorisation. Furthermore, the decomposed resins remains either in the solvent or in the enzymatic solution. These monomers or oligomers are reused for same or novel chemical purposes and the solvent media is recovered for reuse.
At the end, VIBES and BIZENTE establish a global and intersectoral waste management treatment for the collection, sorting and recycling of thermoset based composite materials, looking for an adequate end-of-life route and valorisation of the components.
The implementation of the proposed solutions makes a controlled stream of composite waste possible. The new recycling processes broaden the type of feedstocks that can be used by the bioindustry in the form of monomers and fibres building blocks for the chemical and biotechnological industries.
In the near future, we will find a new generation of high-tech products such as aircrafts, boats, windmills, cars, trains… manufactured with fully recycled complex thermoset composites, making the dream of a planet free of plastics come true.