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Thermal cis‐trans isomerization and temperature‐dependent phase behaviour of polyisoprene‐polyacetylene solutions
Author(s) -
Dai Liming
Publication year - 1997
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1997.021980603
Subject(s) - polyacetylene , isomerization , copolymer , isoprene , polymer chemistry , polymerization , phase (matter) , chemistry , materials science , photochemistry , polymer , catalysis , organic chemistry
Polyacetylene can be solubilized by making copolymers with polyisoprene via anionic polymerization of isoprene using BuLi as the initiator, followed by Ziegler‐Natta copolymerization of acetylene onto the polyisoprenyllithium chains using either Ti(OBu) 4 or CoCl 2 . In the present study, the effects of temperature on cis‐trans isomerization of the polyacetylene blocks and the phase behaviour of the PI‐PA copolymers in solution were investigated. We found that isomerization of the cis ‐polyacetylene blocks in a solution of the PI‐PA copolymer is retarded by some intramolecular barriers, making the cis ‐isomer rather stable. Reducing the temperature below about 12°C was found to cause a phase transformation from the worm‐like structure to spherical micelles in solution.