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Living Carbocationic Polymerization. LVII. Kinetic Treatment of Living Carbocationic Polymerization Mediated by the Common Ion Effect
Authors:Tibor Pernecker  Tibor Kelen  Joseph P Kennedy
Institution:1. Institute of Polymer Science The University of Akron , Akron, Ohio, 44325-3909;2. Central Research Institute for Chemistry of the Hungarian Academy of Sciences , Budapest, P.O.B. 17, H-1525, Hungary;3. Kossuth Lajos University , 4010, Debrecen, P.O.B. 1, Hungary
Abstract:Abstract

The effect of anion concentration on the apparent rate constant of polymerization kA p of isobutylene (IB) induced by the 2-chloro-2,4,4-trimethylpentane (TMPCl)/TiCl4 initiating system using the CH2Cl2/nC6H14 (60/40 v/v) solvent system at ?40 and ?80°C was studied by the use of nBu4NCl. Computer simulation has shown that kA p decreases several orders of magnitude upon the addition of even a very small amount of common anion TiCl?- 5 to the charge. The rate of change is reduced in the concentration range of experimental interest. It was concluded that the decrease of kA p with increasing TiCl ?- 5 concentration is mainly due to the decreasing contribution of propagation by free ions. The contribution (%) of propagation by free ions to the apparent rate of propagation was calculated.
Keywords:
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