Living free radical polymerization in disperse medium: experimental and computational analysis

Abstract

Free Radical Polymerization is one of the most important techniques for the production of polymers, however, it presents limitations regarding controlling the microstructure of the chains. Polymers with high defined structure (low polydispersity and narrow molecular weight distribution) have been obtained from an innovative and promising route: the controlled free radical polymerization that is able to produce polymers with polydispersity close to one. The controlled process has been used in bulk polymerization, however a few works deal with controlled polymerization in disperse medium. When this is the case, most of them deals with mini-emulsion and little has been developed in emulsion area. Nowadays emulsion polymerization is an important technique for commercial production of polymers, because it presents advantages when compared to the other techniques. However its application to the production of controlled polymers is still a challenge, not only because the higher complexity of the system, but also due to the high temperature needed when working with controlled process, that is able to make the system instable and promote thermal polymerization in the bubbles of the monomer. In this work the emulsion polymerization by living free radical polymerization will be studied in experimental and computational level, considering the ab initio process. Styrene will be used as a monomer and the polymerization will be performed in a 1 liter reactor. The experimental data will be used for the model validation and to fit of the parameters. Important properties will be analyzed, such as molecular weights, molecular weight distributions, particle size and particle size distribution, etc.