ELUCIDATING THE MECHANISM AND RATE CONSTANTS IN THE CATIONIC POLYMERIZATION OF STYRENE - LIMITATIONS OF LIVING SYSTEMS

The chemistry and kinetics of various elementary reactions in the cationic polymerization of styrene, including propagation, depropagation, transfer, termination, and initiation, are discussed. The limiting conditions for living systems are then estimated from a master Arrhenius plot of the rate constants of these reactions as a function of temperature. This master plot demonstrates that although polymers with DP almost-equal-to 7 might be prepared at 50-degrees-C, polymers with DP almost-equal-to 1500 could be prepared by decreasing the temperature to -70-degrees-C. The effect of solvent on the relative contribution of the different reactions is also demonstrated. New ''living'' systems are similar to classic cationic systems but with better control due to fast initiation and slower polymerization rates as a result of reversible formation of dormant species.