Precision design of novel bio-based and ethylene-based copolymers: application to advanced nanocomposites

Polyolefins are an inexpensive class of compounds that can be used to prepare a plethora of different materials. Poly(ethylene) is the worldwide most produced polymer and is mostly synthesised by free radical polymerisation or catalytic coordination insertion using high temperature and pressure. The controlled radical polymerisation of ethylene is very difficult to achieve because of secondary reactions of this unconjugated monomer, e.g. chain transfer and termination reactions. Cobalt-mediated radical polymerisation (CMRP) represents a solution to control its polymerisation in mild conditions: in a reversible deactivation mechanism, a cobalt complex reversibly traps the active growing chains and converts them into dormant species, avoiding side reactions and allowing for a controlled polymerisation. Using CMRP, statistical copolymers of ethylene and vinyl acetate (VAc) have been synthesised, as well as block-like and block copolymers. Furthermore, functionalisation of the α- and ω-chain ends are now possible. Incorporating other monomers, e.g. vinyl esters or vinyl amides, into an ethylene copolymer by CMRP will lead to completely new and highly interesting materials which may act as compatibilisers for the dispersion of natural polymers, such as cellulose, into various polymer matrices. The goal of this work is to design novel well-defined functional polyethylenes that are expected to improve the dispersion of natural polymers into polyolefins.