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Séminaire Chimie ED459

Biobased and (bio)catalysed covalent adaptable networks – catalytic control of material properties

Dr. Camille Bakkali Hassani, C.R. CNRS (ICGM Institut Charles Gerhardt Montpellier, UMR 5253 CNRS, UM, ENSCM)

publié le , mis à jour le

Le Jeudi 25 janvier 2024 à 14h
ENSCM, Amphithéâtre Godechot (240 av. Émile-Jeanbrau)

Polymers have revolutionized our daily life during the last century and are today ubiquitous and irreplaceable in a wide range of applications. The use of petrochemical-based precursors associated with long-termed (bio)degradability and a poor global waste management make also polymers one of the major ecological concerns of our time. Designing sustainable polymeric materials prepared from renewable resources and capable of inherent reprocessability, recyclability and degradability appear necessary to address the current environmental challenges.

Covalent Adaptable Networks (CANs) are chemically crosslinked materials able to exchange covalent bonds thus combining advantages of both thermosets (good thermo-mechanical properties, chemical resistance, etc.) and thermoplastic (reshaping and recycling). Transesterification has been one of the most studied exchange reactions and despite numerous developments in catalyst design and activity, CAN chemistry has limited its approach to a few candidates (Zn-based, Tin derivatives, phosphines or guanidine-based compounds).

We developed a new approach using a peculiar lipase from Pseudomonas stutzeri (lipase TL) to prepare biobased epoxy-acid CANs. Combining molecular model reactions and enzymatic assays, we demonstrated that Lipase TL was able to simultaneously promote acid−epoxy addition and transesterification reactions below 100°C and solely the acid−epoxy addition after denaturation at T > 100°C. Prototype CANs were obtained using various bifunctional monomers with lipase TL and can be integrated in emergent applications such as soft robotic. Apart from transesterification, we will also discuss original catalytic approaches to prepare poly(hydroxy)urethane CANs and recycle polyurethane thermosets by transcarbamoylation.

Contact local ICGM : Dr. Camille Bakkali Hassani (dépt. D2 C3M)

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