Living Free Radical Polymerization in Continuous Miniemulsion Reactors

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

Research: A large percentage of polymers (plastics and synthetic rubbers) are made via free radical polymerization. Unfortunately, this technology does not allow for accurate control of the molecular structure of the polymer produced. Living free radial polymerization (LRP) is a recent technology that allows for substantially more control over molecular structure, i.e., it allows for the preparation of well-defined vinylic polymers with unique architectures. Most research in LRP to date has involved batch reactors in which all ingredients are added to the reactor at the beginning of the reaction. In addition, most LRP studies to date have involved processes that use organic solvents. These solvents are expensive, and can pose environmental and health threats. The advent of living radical polymerization (LRP) processes over the last few years More stringent environmental and health concerns are driving the polymer industry to benign processing. For free radical polymers this includes systems in which water is substituted for an organic solvent. Miniemulsion polymerizations in particular have garnered increasing attention due the absence of organic solvent, their robust nature and lack of interphase mass transfer. Recent studies combining miniemulsion techniques with LRP have demonstrated added benefits such as increased rate of polymerization. Continuous reactors are associated with high volume, low operating and labor costs, and most importantly, may be able to provide control of molecular structure, which can be difficult in a batch or semibatch reactor. With this in mind, this proposal will carry out a comprehensive study of LRP using the RAFT technique in continuous miniemulsion reactors. In particular, the ability of trains of CSTR's with inter-reactor monomer feed to create unique, new block copolymers will be evaluated. Specific objectives include evaluating: effect of reactor type, effect of control agent type, polymer composition control, and reactor-polymer property relationships. Impact: If the results are successful, the technology could be the basis for a low-cost, environmentally clean, commercially viable manufacturing method for paints and coatings. Development of this new methodology could also be a great boon for the polymer industry in general.