Premium
New processes and designed polymers by cationic techniques
Author(s) -
Kennedy Joseph P.
Publication year - 1991
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19910470106
Subject(s) - isobutylene , thermoplastic elastomer , copolymer , cationic polymerization , polymer chemistry , polymer , living cationic polymerization , polymerization , monomer , living polymerization , styrene , materials science , polymer science , anionic addition polymerization , elastomer , ring opening polymerization , radical polymerization , composite material
The most important recent development in cationic polymerizations is the emergence of living polymerizations leading to a variety of new potentially useful well‐defined macromolecules under conventional laboratory conditions. Three requirements have to coexist for living carbocationic polymerization to occur: Controlled initiation controlled chain‐transferless propagation and controlled (quasiliving) termination. The first part of this presentation will briefly discuss the road to these three key requirements. The second part will concern practical consequences and select systems. The synthesis of narrow‐molecular‐weight‐distribution (M̄ w /M̄ n = 1.1 ‐ 1.3) tert‐chlorine telechelic polyisobutylenes over a wide molecular weight range (M̄ n from ∼1000 to ∼125, 000 g/mole) will be outlined together with recent work on aromatic olefins, e.g., styrene, tert‐butylstyrene and p‐chlorostyrene. These developments led to the combination of these living systems for the synthesis of block copolymers by sequential monomer addition. Tri‐ or higher block copolymers comprising glassy outer segments and rubbery inner segments, for example, poly(styrene‐b‐isobutylene‐b‐styrene, poly(p‐chlorostyrene‐b‐isobutylene‐b‐p‐chlorostyrene), have been prepared. These new thermoplastic elastomers exhibit phase‐separated microstructures and an interesting combination of physical‐mechanical properties.