ABSTRACT
I. GENERAL CONSIDERATIONS The literature relative to block copolymers splits into two very different parts. A majority o f the publications, mainly patents, are relative to mixtures o f block copolymers and homopolymers; they are poorly characterized, with the exception o f elementary analysis, and at the best a limited spectroscopic investigation that does not permit one to distinguish between the block copolymers and the corre sponding homopolymers. On the other hand, an increasing number o f articles and reviews describe well-defined products, and often their preparation associates different techniques, for instance, living cationic and mediated radical polymer ization.
