Abstract: The present invention relates to a new manner of grafting various organic groups or polymers; it is concerned particularly with the grafting of vinyl, acryl, vinylidene or other chains on polymers of olefines, diolefines, aromatic vinyl compounds and similar compounds; a new catalytic system is used for effecting such a grafting, wherein a deactivated polymer is brought into contact with at least one organometallic compound and at least one generator of free radicals out of the presence of air.

Abstract: The present invention describes a process of producing block copolymers from monomers of different types by polymerization in two successive steps. The first step consists in polymerizing monomers of a first type by means of coordinated anionic catalysts comprising organo-metallic compounds of a metal of the Group IA, IIA, IIIA, or mixtures thereof of Mendeleev's Periodic Table of Elements, associated with a transition metal compound of Group IV to VIII and the second step comprises polymerizing a second type of monomer in the presence of the polymer formed in the first step and in the presence of free radical catalysts, wherein 0.01 to 100 moles of an adjuvant per mole of transition metal compound is added to the reaction medium of the first step and this adjuvant consists of a compound MY.sub.