In the future, the selective sorting of the different plastics may no longer be necessary for the purpose of recycling. Scientists from ESPCI Paris and the CNRS have developed a process that will transform them directly “alloy vitrimère” capabilities surprising. Discovery.
Turbines, piping, electronics, or robotics, developments in technology require materials with higher performance in terms of lightness and resistance, but also cost and environmental footprint. However, the common plastics do not meet all of these requirements. But researchers from the Ecole supérieure de physique et chimie industrielles (ESPCI) in Paris have discovered a reaction of metathesis* which leads to the creation of a “super-polymer” having a carbon skeleton.
The “vitrimères”, a class of materials designed by Ludwik Leibler and his colleagues (D. Montarnal, M. Capelot, F. Tournilhac) are dynamic networks that could “revolutionize the world of plastics” since they combine mechanical strength, thermal and chemical. And the process developed by scientists does not require a catalyst, “which is a real advantage in economic and ecological“. Starting from the basic ingredients of the classic, plastic regular, non-sorted, so it would be possible to obtain high-performance materials. The proportions of the various components and the conditions of implementation (injection, casting, blowing, extrusion, thermoforming) would allow to obtain the desired characteristics. The press release of the CNRS says : “The vitrimères obtained from polystyrenes, acrylates or polyethylene exhibit improved mechanical and thermal resistance as starting materials, without compromising the ability of repair, welding and recycling“.
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Another advantage is that the vitrimères are less susceptible to liquids that usually craquellent the pieces of plastic or composites. During an experiment, scientists measured the appearance of cracks in an object in polyethylene and placed in soapy water after only 30 hours, where an object vitrimère withstands more than 350 hours. The material could therefore serve as an alternative to some of the protective coatings in pipes, tanks, glass or mechanical parts. Do not end to be amazed by their discovery, the researchers also noted that the reaction could operate on the surfaces : “very strong adherence between the vitrimères made from plastics completely incompatible is obtained“. A peculiarity of most which would open up prospects this time in the field of packaging or in one of the tires. The promise of obtaining, by recycling what was once considered waste, components improved, more rigid, impact-resistant or tear resistant, and impervious to solvents. The ESPCI in Paris has filed patents on the technology which proves to be promising.
(*) Reaction of metathesis : to exchange one or more atoms between the molecules whose structures are related to each other, without deterioration of the chemical bonds existing.