ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
While many well defined sequential copolymers have been synthesized by anionic and some by coordination polymerization techniques, cationic methods have not been exploited in this regard. This lecture focuses on “macromolecular engineering” by cationic techniques and summarizes the many recently developed and largely unpublished methods by which a great variety of sequential copolymers and modified polymers can readily be prepared. A new scheme for macromolecular engineering by carbocationic mechanism is proposed. Controlled initiation as a means of introducing head-groups into polymers or of graft-copolymer syntheses is described. Control of chain transfer to monomer became possible by the use of bifunctional initiator-chain transfer agents (inifers) or by proton sponges. The synthesis of telechelic α,ω-dichlorides, and -diolefins is outlined. α,ω-(Di-tert-chloro) polyisobutylene, a new symmetrical telechelic prepolymer has been used to prepare poly(α-methylstyrene-isobutylene-α-methylstyrene) thermoplastic elastomeric triblocks. Consequences of controlled termination are illustrated by the synthesis of diblock copolymers. Finally, by a combination of mechanistic elements, a system for macromolecular engineering by cationic techniques is outlined.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1979.020031979101
