A novel synthesis of starpolymers from a soft-hard-soft triblock has been reported. The triblock was obtained by adding isobutene (IB) "in situ" to the living styrene (S) polymerization mixture initiated by the p-dicumy1chloride/TiCl4/pyridine system. Microphase separation was observed by transmission electron microscopy and differential scanning calorimetry. Treatment of the PIB-PS-PIB triblock with CC14 in the presence of AlCl, led to the starpolymer and the number of arms was estimated by size-exclusion chromatography to be 20. ZUSAMMENFASSUNG:Es wird uber eine neuartige Synthese fur Sternpolymere aus einem Weich-hartweich-Triblockcopolymeren berichtet. Das Dreiblock-Copolymere wurde durch insitu-Addition von Isobuten (IB) zu einer mit Dicumylchlorid/TiC14/Pyridin initiierten lebenden Polymerisation von Styrol (S) erhalten. Untersuchungen mittels Transmissionselektronenmikroskopie und Differentialkalorimetrie zeigen eine Mikrophasenseparation des PIB-PS-PIB-Copolymeren. Durch Umsetzung des Triblock-Copolymeren mit CC14 in Gegenwart von AlCl, wurde das Stempolymere erhalten, dessen Anzahl der Arme mittels GroBenausschluBchromatographie zu 20 bestimmt wurde.

A thorough kinetic investigation was done by measuring the optical density of reaction mixtures of the pDCC/BCl3 initiating system in the presence and in the absence of monomer and added salt at 500 nm and at −80°C. The absolute rate constants of elementary steps of the ion generation and cationation were evaluated by computer using a fitting method for determination of the parameters occurring in the kinetic model. The key activated species of the mechanism are identified to be colorless donor‐acceptor complexes. The color of reaction mixtures is caused by ionized species. On the basis of the calculations and other evidences, a well‐established mechanism is proposed. Both ‐tC‐Cl and ‐tC‐OH endgroups were found by MS/EI. GPC analysis of the reaction products indicates that the major product is dimer under the reaction conditions applied.

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