Inifer concept

The first part concludes with a discussion of the similarity between the mechanisms of initiation and chain transfer, the appreciation of which led to the inifer concept, which in turn yielded new telechelics, networks, sequential copolymers, etc. The second part of this presentation focuses on practical consequences of understanding details of the mechanism of initiation. The synthesis of a new family of telechelic linear and tri-arm star polyisobutylenes will be described. Among the new prepolymers are telechelic olefins, epoxides, aldehydes, alcohols, and amines. The preparation of new ionomers and polyisobutylene-based polyurethanes will be outlined and some fundamental properties of these new materials will be discussed. 

The Inifer Concept. A detailed analysis of the respective mechanisms of initiation and various chain transfer processes showed that the fundamentals of initiation by alkyl halides and chain transfer to alkyl halides are indeed very similar. It is postulated that an alkyl halide that is able to initiate car-bocationic polymerizations, may also be able to function as a chain transfer agent. Schematically (1) ... 

Three methods were developed to overcome transfer to monomer. These are (1) use of inifers (2) use of proton traps and (3) establishing conditions under which the rate of termination is much faster than the rate of transfer to monomer. The first one, the inifer method, is particularly useful in formation of block copolymers. It allows the preparation of head and end (a and to) functionalized telechelic polymers. Bifunctional initiators and transfer agents (inifers) are used. The following illustrates the concept ... 

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