Ni. Pakuro et al., INVESTIGATION OF THE INITIATION REACTION OF ISOPRENE POLYMERIZATION WITH 2-ETHYLHEXYLSODIUM IN HEPTANE, Macromolecular chemistry and physics, 198(12), 1997, pp. 3855-3861
The kinetics of the initiation of isoprene polymerization in heptane w
ith the hydrocarbon-soluble alkylsodium compound 2-ethylhexylsodium wa
s studied. Initiation rates were estimated from the induction period a
nd by measuring UV spectra of polyisoprenyl-sodium (lambda(max) = 304
nm) during the course of polymerization. The initiation reaction is fi
rst order in initiator both in the course of the reaction and with res
pect to the starting concentration of the initiator. The same result i
s obtained when 2-ethylhexyllithium is used. The initiation rate const
ants are: k(i) = 1,6.10(-3) and 5,5.10(-4) L/(mol.s) for sodium and li
thium compounds at 26 degrees C, respectively. Aggregated forms of org
anoalkali compounds are suggested to take part in the initiation react
ion of isoprene polymerization.