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Kinetics of isoprene polymerization in the presence of 2‐ethylhexylsodium and its mixtures with 2‐ethylhexyllithium in hydrocarbon solvents
Author(s) -
Shcheglova Larisa V.,
Pakuro Natalia I.,
ArestYakubovich Alexander A.
Publication year - 1998
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/(sici)1521-3935(19980601)199:6<1025::aid-macp1025>3.0.co;2-r
Subject(s) - isoprene , kinetics , polymerization , hydrocarbon , chemistry , polymer chemistry , organic chemistry , copolymer , polymer , physics , quantum mechanics
The anionic polymerization of isoprene with 2‐ethylhexylsodium soluble in hydrocarbons in the absence of electron donor additives has been studied. The kinetics of the propagation reaction is shown to strongly depend on the solvent used. In toluene, the reaction order in initiator appears to be fractional, its value being dependent on the initiator concentration, while in heptane the first order is known to be followed. For polymerization in toluene, a scheme is suggested where monomeric and tetrameric active species are supposed to take part in propagation. With a non‐linear regression fit, apparent constants in the equation describing this scheme were evaluated. The kinetics of isoprene polymerization with the mixed 2‐ethylhexylsodium/2‐ethylhexyllithium initiator, as well as UV spectra of the living polymers obtained, were also studied. Formation of complex active species is suggested.