Microstructures of Polymers Prepared by Free-Radical Polymerization

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9312048 Starnes This research will be directed toward the elucidation of the detailed structures and polymerization mechanisms of poly(vinyl acetate), various vinylidene chloride polymers, and poly(vinyl chloride). All of these polymers have great technological significance, and all of them are made commercially by free-radical polymerization. Much of the effort will relate to the identification and quantification of structural defects in the polymers such as long and short branches, long-chain ends, adventitious unsaturation, adventitious structures containing oxygen, and groups derived from solvents. The principal analytical tool will be high-field Nuclear Magnetic Resonance, and both the poly(vinyl chloride) and the vinylidence chloride polymers will first be converted chemically into the corresponding "polyethylenes" in order to facilitate the analyses. Resonance assignments will be confirmed by comparing the polymer spectra with those of reference models that are to be synthesized during the course of the project. In the case of poly(vinyl acetate), a major goal will be to understand fully the striking effects of aromatic solvents on the polymerization chemistry and kinetics. The work with poly(vinyl chloride) and the polymers of vinylidene chloride will be concerned especially with the structural defects that contribute to the thermal instability of these materials. Results obtained from the project should suggest ways of modifying the polymerization processes in order to form polymers with improved properties. ***