Toshimitsu Suzuki, Y. Tsuji, Yoshihisa Watanabe
Aug 1, 1979
Citations
0
Influential Citations
6
Citations
Journal
Polymer Journal
Abstract
Abstract25.0 MHz 13C and 220 MHz 1H NMR investigations were carried out on living anion chain ends of oligomeric 1-phenyl-1,3-butadiene (1PB) in order to reveal the anionic polymerization mechanism. The propagating species of 1PB can be concluded to be the 4,1 anion. Lithiated 1-phenyl-2-butene (1P2B) was employed as a model anion of the propagating species of 1PB. A negative charge on the chain end delocalizes at α-carbon and phenyl ring, and delocalization to γ-carbon is small regardless of the polymerization solvent. Therefore, the monomer attacks a-carbon and consequently the in-chain 1,4 unit is predominant even in THF solvent. These behaviors are quite different from those observed in oligomeric butadiene and/or isoprene chain ends. In THF the living chain end is regarded as only trans-4,1, whereas in hydrocarbon media it is an almost equal mixture of trans- and cis-4,1 structures.