The synthetic polymer world has seen a paradigm shift during the last decades since the advent of living/controlled polymerization techniques. These techniques enable a precise control over the macromolecular architecture (molar mass, functionality, monomer enchainment, etc.), thus allowing to engineer “on-demand” synthetic polymers that present the desired properties required for the targeted application. For instance, they can be used for preparing functional polymers that will favour the dispersion of (nano)fillers (carbon nanotubes, silica nanoparticles, metal nanoparticles, etc.) or other polymers (natural or not) in polymer matrices to which they present no affinity. These so-called compatibilizers are most often required to improve the compatibility of the nanofillers with the matrix and to prepare advanced nanocomposites or to homogenise polymer blends. Polyolefins are important polymer matrices, in which the dispersion of polar fillers is extremely challenging.
Although a large panel of controlled polymerization methodologies exists for vinyl monomers, none of them is universal and a combination of different techniques has most often to be used if challenging monomers have to be copolymerized (like ethylene and polar vinyl monomers), which renders the synthesis sometimes difficult or impossible. Moreover, the quest for greener polymerization processes is a strong incentive to develop synthetic methodologies that are efficient under mild experimental conditions and in environmental-friendly media (water for instance). Bio-based monomers bearing vinyl esters, vinyl amides, α- or α,α-dialkyl substituted olefins are valuable building blocks for the design of advanced sustainable materials. However, only few polymer architectures are made available because most of the controlled polymerization techniques are not efficient for those monomers. Since such monomers can be obtained in efficient (often catalytic) procedures from renewable feedstocks (i.e. plant oils and terpenes), we will focus our investigations on such demanding monomers for the design of novel bio-based materials. For example, vinyl esters and amides can be obtained from fatty acids and used as yet uninvestigated monomers in controlled radical polymerization (CRP) techniques in order to bring the desired properties. Moreover, α-olefins can be obtained from unsaturated fatty acid derivatives via olefin cross-metathesis with ethylene and α,α-dialkyl moieties are found in certain terpenes (i.e. ß-pinene) avoiding the need for further functionalization.
In this project, we aim at exploiting a novel controlled radical polymerization technique for the precision design of novel bio-based functional materials that are not accessible by other controlled polymerization techniques. In the frame of this work, we will investigate the preparation of copolymers that may act as compatibilizers for the dispersion of natural polymers into various polymer matrices, including polyolefins. This will first be achieved by copolymerizing the above-mentioned renewable monomers with ethylene. The bio-sourced monomer will be selected to produce ethylene-based copolymers that may interact with the natural polymer and improve its dispersion in polyolefins. The architecture of the copolymer, molar mass, main chain and chain end-functionalities will be important parameters to be tuned to design the optimal compatibilizers. Homo- and copolymers of the above-described monomers (without ethylene) will also be prepared for designing compatibilizers for dispersion of the natural polymer in other matrices. The properties of these compatibilizers can also be tuned by post-polymerization modification and/or variations in the applied monomer structure.
The research topic will therefore consist in (1) the synthesis of functional bio-sourced vinyl monomers, (2) their homo- and co-polymerization with ethylene and/or other vinyl monomers using a new controlled radical polymerization technique, (3) evaluating the capacity of the most promising copolymers to disperse natural polymers in various polymer matrices.
Well-beyond the preparation of novel compatibilizers, the synthetic route developed in this work will bring innovation in the design of unprecedented functional bio-sourced materials that are of great promise in various research fields.
 M. A. R. Meier, J. O. Metzger, U. S. Schubert, Chem. Soc. Rev. 2007, 36, 1788-1802.
 : A. Kermagoret, A. Debuigne, C. Jerome, C. Detrembleur Nature Chemistry 2014, 6, 179-187.
The research will be performed in a close collaboration between two academic research groups [the University of Liege (ULg) in Belgium and the Karlsruhe Institute of Technology (KIT) in Germany]. University of Liege (ULg) has a long history in the development of novel controlled polymerization techniques and in the precision design of (multi)functional copolymers. Karlsruhe Institute of Technology (KIT) has a strong expertise in the preparation and application of bio-sourced monomers. The third partner, Ineos Services Belgium, is a world leader company in the polyolefin business. The PhD student will share his/her time between these 3 partners (11 months at KIT, 24 months at ULg and 1 month at Ineos).
Center for Education and Research on Macromolecules, University of Liège, Belgium
synthesis of the bio-sourced copolymers of different structures (random, block, etc.) and preliminary investigation of their efficiency as compatibilizers
Institute of Organic Chemistry, Karlsruhe Institute of Technology, Germany
synthesis of the bio-sourced monomers
Industry Partner: Ineos, Belgium
olefins polymerization at bench scale (close to industrial conditions) and preparation of mixtures of the prepared compatibilizers with the natural polymers and polyolefins.
Host Country (employment): Belgium
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