Pheno-recycle: phenolic resin finally recyclable
The result of collaboration between researchers at the Institut Charles Gerhardt de Montpellier (ICGM) and Saint-Gobain, the Phéno-recycle project has developed innovative processes for recycling phenolic resin. Pheno-recycle is one of the chemical industry's most solid wastes, previously destined for incineration or landfill. Supported by the Pôle universitaire d'innovation this virtuous partnership has met with dazzling success.
They overcame an industrial deadlock in less than three years. Hand in hand, researchers at Montpellier's Charles Gerhardt Institute (UM/ENSCM/CNRS) and Saint-Gobain have finally found a way to recycle phenolic resin, one of the chemical industry's most resistant and, until now, incompressible waste products. And to round off this first fruitful collaboration, the two partners, boosted by the Pôle Universitaire d'Innovation, have just filed a patent application.
Resistant thermosetting polymers
The story begins in 2021. Saint-Gobain approached the ICGM, which has expertise in the synthesis of phenolic resins with reduced environmental impact (formaldehyde-free) and " attaches particular importance to recycling and the more virtuous use of resources ", stresses Vincent Ladmiral, research director at the institute.
Saint-Gobain uses these phenolic resins in the design of insulating materials such as glass wool, and in the manufacture of abrasives such as sandpaper.
"There's a problem with these materials, which have a very long service life. They are thermosetting polymers, essentially made up of the carbon-carbon bond, one of the strongest in chemistry. They are extremely resistant to ageing and chemical attack. They are also highly thermally stable. So, by definition, they are not easy to recycle", explains the researcher.
Small, reusable molecules
In concrete terms, via an Agence Nationale de la Recherche Technologique (ANRT ) thesis funded by Saint-Gobain from November 2022, the teams have found a way to cut this resin into smaller, reusable molecules. After publishing an initial proof-of-concept in 2023, the team has joined the "Companies & campus" scheme, a tool developed as part of the Pôle Universitaire d'Innovation and designed to enhance collaborations between public research and the business world.
Thanks to a 50,000 euro grant from the Pôle Universitaire d'Innovation, the team was able to hire an additional engineer for 12 months. " We already had the process, we already had promising recycling routes, but Companies&campus enabled us to go further in understanding the depolymerization mechanism and the structure of these oligomers", says Organe Petit, head of the eco-processes and innovations for chemistry research and development group at Saint-Gobain Recherche Paris and coordinator of Saint-Gobain's sustainable chemistry network.
"Winning on all fronts
In the course of their research, scientists have succeeded in turning these resins into recyclable residues. They have also succeeded in transforming them into vitrimers, with reversible properties. Invented in 2011, this new class of polymers corresponds to materials that can be melted and recycled at will... A godsend at a time of necessary ecological transition. " It' s a win-win situation," says Vincent Ladmiral.
If Saint-Gobain implements this technology, it could enable these recycled materials to be used in the manufacture of new products, thereby helping to minimize the use of planetary resources. "We have high hopes for these materials, which could prevent the accumulation of thermoset polymers without a recycling solution. Until now, their end-of-life was limited to incineration or landfill.... So from both a scientific and industrial point of view, this is a great success", sums up the ICGM researcher.