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Research themes

Polyolefins are the major commodity polymers. Their annual production is around 170 million tons per year and their annual growth rate of around 3-4% is remarkable. This family alone represents more than 60% of plastic production.

Although the polymerization catalysis of olefins has been based, since the 1950s, on the heterogeneous Ziegler-Natta (titanium) and Phillips (chromium) catalysts, the existence of several active species is a limitation for certain applications of olefins. The use of well-defined molecular complexes makes it possible to produce "tailor-made polyolefins" with original properties or improved mechanical performances.

My research aims at developing olefin and conjugated dienes polymerization catalysts in homogeneous and heterogeneous media. The challenge is not only to develop well-defined molecular catalysts for the production of advanced polyolefins, but also to adapt them to heterogeneous industrial processes that require supported catalysts. As technology transfer to industry is a key issue, process parameters are taken into account in chemical studies.

 

 

 

 

Current projects

My main research activities concern both the development of advanced polyolefins in solution process and of supported molecular catalysts for slurry and gas phase processes.

In the case of polymerization in solution, we produce advanced elastomers and end-functionalized polyethylenes.

• The preparation of new elastomers by copolymerisation of olefins and conjugated dienes using neodymium metallocene catalysts is a theme that I have been pursuing for many years in the laboratory. We have discovered that neodymium metallocene catalysts have the unique ability to copolymerise ethylene and butadiene. The developed catalysts have enabled the preparation of a wide range of copolymers of ethylene and butadiene and in particular new elastomers with 1,2-cyclohexane units in the polymer chain backbone. These cyclohexane units are formed by intramolecular cyclisation involving Vinyl units from the inserted butadiene. These new elastomers are referred to as EBR (Ethylene Butadiene Rubber) in the industry and provide tyres containing them with unique properties. In the joint laboratory ChemistLab, we are developing with Michelin new generations of elastomers by addressing the entire life cycle of these materials.

• The lack of polarity in polyolefins is a limitation for adhesion or printing applications and for compatibility with other organic or inorganic materials. The controlled introduction of reactive functions into polyolefins is an important objective, as it will allow access to reactive building blocks opening the way to the synthesis of new materials benefiting from all or part of the properties of a polyolefin. Thanks to a controlled polymerisation system, we have produced a range of chain-end functional polyethylenes. These polymers are produced on a kilogram scale by the SME Activation .

 

In the field of supported molecular catalysts, we have developed the concept of activating support. These new activators permit to immobilize the active species on a carrier during the activation of the precatalyst. The catalysts have been successfully tested on a pre-industrial scale.

 

 

Partner, links and extras

Most of my present project are linked to the joint laboratory with the Michelin : ChemistLab. This interdisciplinary laboratory masters a global chain of knowledge combining chemistry and reaction engineering to design, synthesize and evaluate the physicochemical and mechanical properties of new elastomers.

•  Ms. Ariane Desgranges who is working on the development of new ethylene butadiene rubber as part of the project ChemistLab. Ariane has a Cifre scholarship sponsored by Michelin. 
• Ms. Ludmilla Verrieux. Ludmilla is supervised by Dr Lionel Perrin (ICBMS – UMR 5246). She is working on the modelisation of olefin polymerization mechanisms using DFT. Ludmilla has a Cifre scholarship sponsored by Michelin as part of the project ChemistLab. 
• M. Samy Alioui is working on the development of thermoplastic elastomers as part of the project ChemistLab. Samy has a CNRS 80PRIME scholarship. 
• Dr. Marvin Langlais is also working on the development of thermoplastic elastomers as part of the project ChemistLab. Michelin sponsors the project of Marvin. 
• Dr. Marion Duval is working in the field of olefin polymerization in gas phase. Michelin sponsors the project of Marion.