Catalysts for the Controlled Polymerization of Conjugated Dienes

<p>Since the beginning of the 1960s the coordinative polymerization of conjugated dienes has continuously improved. Today chemists know how to polymerize conjugated dienes stereospecifically and in a controlled fashion both petro-sourced (nowadays also bio-sourced) and those of natural origin. The industry has greatly improved the performances of the catalytic systems-covering a wide range of elements including metals from groups 4-6 and 8-10 and rare earths-with the aim of optimizing the preparation of synthetic polymers for a large range of industrial applications. Nowadays there is a better understanding of the polymerization mechanism involving allyl-active species thanks in particular to the support of more efficient calculation methods. In addition statistical copolymerization of 13-dienes with olefin or styrene comonomers and innovative approaches to coordinative chain transfer polymerization allow the production of copolymers with controlled topology while a last challenge is about to be solved with the preparation of stereoregular polydienes that are also end-functionalized. This issue brings together several important aspects of this chemistry that remain at the forefront of both academic and industrial research.</p>