第343回化学システム工学専攻公開セミナー Supercritical fluid technology: a scalable approach for advanced material design and recycling What is about sustainability?
- 2019年10月3日(木) 15:00-17:00
|講演題目||Supercritical fluid technology: a scalable approach for advanced material design and recycling What is about sustainability?|
|講演者||Prof. Cyril Aymonier
Institute for Solid State Chemistry Bordeaux(ICMCB), CNRS and University of Bordeaux
|概要||Supercritical fluid flow synthesis technologies are developed from the beginning of the 90’s in the field of advanced materials by design.
This technology of material processing is continuous, fast (few tens of seconds), sustainable and scalable and gives access to high quality nanostructured materials with unique physico-chemical properties, meaning which can not be obtained with other synthetic methods.
After a brief introduction on supercritical fluids, this presentation proposes to describe the principle of the preparation of advanced materials using this continuous process. A focus will be proposed on the in situ characterizations developed in the last 10 years to be able to understand, model but also to master the formation of nanostructures in supercritical fluids. As an illustration, we will present the first proof of the synthesis in few tens of seconds of geominerals, namely talc, in a continuous millifluidic process. Very interestingly, this synthetic talc exhibits unique properties as its hydrophilicity knowing that naturel talc is hydrophobic. In this new field of geomineral synthesis, we went one-step forward with the demonstration of the possibility to prepare highly crystalline geominerals in just few seconds again but under thermodynamically metastable conditions with the synthesis of the torbermorite mineral which is not abundant in nature but very interesting in the construction industry. The mastering of the chemistry coupled with one pot multi-step processes opens the road towards the continuous design of multifunctional materials as illustrated with functional layer double hydroxide. All these materials can now be produced from laboratory scale for research & development investigations to pilot scale for industrial purposes.
Beyond the design of advanced nanostructured materials, near- and supercritical fluids are also powerful reaction media to offer innovative processes in the field of material recycling. This will be illustrated with the recycling of carbon fibres from carbon fibre reinforced polymers (CFRPs). Compared to pyrolysis, fluidized bed and low temperature processes, which are other studied approaches for CFRPs, solvolysis in near- or supercritical fluids is a great alternative to recover fibres as it provides a high retention of mechanical properties and fibre length and a high potential for material recovery from resin.
Other examples will concern the recycling of scrap magnets and food packaging.
The benefits of the sub- and supercritical continuous route include not only better performances for advanced applications but also environmental issues associated with the synthesis process. This will be emphasized with the studies performed using LCA approaches coupled with risk assessment ones.