LIVING CARBOCATIONIC POLYMERIZATION OF STYRENE IN THE PRESENCE OF PROTON TRAP

The living polymerization of styrene was achieved with the 2,4,4-trimethyl-2-pentyl chloride/TiCl4/MeCl:methylcyclohexane 40:60 v:v/80-degrees-C polymerization system in the presence of di-tert-butylpyridine in concentrations comparable to the concentration of protic impurities. It was determined that the living nature of the polymerization is not due to carbocation stabilization. The polymerization is second order in TiCl4. Side reactions, namely polymerization by direct initiation and intermolecular alkylation, are operational, and a careful selection of experimental conditions is necessary to minimize their effect and obtain apparently living behavior. Polymerization by direct initiation can be minimized by increasing the initiator concentration, and intermolecular alkylation can be reduced by quenching the polymerization system when the conversion reaches close to 100%.