Vitrimers: from dynamics of exchange reactions to thermoset composites' welding
|Dates:||9 February 2018|
|Times:||11:00 - 12:30|
|What is it:||Seminar|
|Organiser:||Department of Materials|
Vitrimers are crosslinked organic networks yet able to flow thanks to a unique feature: a chemical structure that allows network's links to exchange under thermal stimulation while keeping the number of links constant.
Vitrimers have first been illustrated by the group of Leibler through the design of poly-hydroxy ester networks in which connecting ester bonds can exchange by transesterification.
Such networks are insoluble like thermosets but when heated and in the presence of well chosen catalysts, exchanges are fast and the material can flow by reorganization of the network's topology. They thus proved to be heat-processable,
recyclable and weldable like thermoplastics.
The unusual combination of properties of vitrimers is very appealing both fundamentally and practically, in particular for composite materials. As opposed to the infinite viscosity of thermosets and their definitive shape after curing,
epoxy vitrimers exhibit a high but finite viscosity which permits to envision new shaping, reparation and postcure techniques.
François Tournilhac received his master's degree in engineering (Ecole Centrale, Paris) in 1984 and a PhD in physical chemistry (Université Pierre et Marie Curie) in 1989. He was recruited in 1989 as a CNRS researcher and since
then he has continued his research mainly at ESPCI-Paris. As a soft matter chemist, he has dedicated himself to the design and synthesis of materials and the demonstration of new effects in organic semiconductors, liquid crystals,
block copolymers and composites. In 2000, he joined the team of Ludwik Leibler. Inspired by industrial problematics, their collaboration aims at the discovery of new effects (eg phase separation induced by an electric field gradient)
or design new materials showing unusual combination of properties (eg self -healing rubber, vitrimers).
Role: Directeur de Recherche CNRS
Organisation: Soft Matter and Chemistry Laboratory, ESPCI-Paris
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