MWD Prediction in PS Synthesis Using Asymmetric Bifunctional Initiators.

ASTEASUAIN, MARIANO; BRANDOLIN, ADRIANA; SARMORIA, CLAUDIA

Viña del Mar

Simposio; II Simposio Binacional Argentino-Chileno de Polímeros; 2003

Universidad de Chile

There has been an increasing interest in the study of the free radical polymerization of vinyl monomers using asymmetric bifunctional initiators. These initiators are frequently used in industry because they allow simultaneous achievement of high polymerization rates and high molecular weights. They do, however, originate a rather complicated kinetic scheme due to the coexistence of several polymeric species.We focus on polystyrene synthesis using asymmetric bifunctional initiators. Several models describing this system that are reported in the literature aim mainly at the prediction of monomer conversion and average molecular properties. In this work we extend one of them to allow MWD prediction. For this purpose we apply the probability generating function (pgf) technique we have previously developed.In spite of the complexity of the kinetic scheme, the pgf technique allows the MWD to be easily and efficiently modeled. In the absence of experimentally measured MWD, we validated our model comparing average molecular weights obtained from the calculated MWD with experimental data of those magnitudes reported in the literature. Good agreement was obtained.