Applications of microemulsions in producing monomers and polymers: Epoxidation of soybean oil and design of polymers with regulated molecular weight and specified end-groups

Microemulsions are thermodynamically stable, optically clear dispersions of oil and water which form spontaneously in the presence of appropriate surfactants and cosurfactants. Surfactants lower the surface tension to ultra-low values that allow small droplets of the dispersed phase to form. The broad objective of this research is to employ the unique properties offered by microemulsions to produce monomers and polymers by modifying the structure of soybean oil such that it incorporated hydroxyls and epoxide groups, and producing acrylate polymers with regulated molecular weight and specified end-groups.; In the first part of this study, methods to produce soybean oil/water microemulsions using nonionic surfactant Mazol in the presence of a series of terminal alcohols (methanol through hexanol) have been presented. The different types of microemulsion phases (o/w, bicontinuous, w/o, or single phase) observed under different conditions (temperature and component concentration) have been mapped out in "fish" and Gibbs phase diagrams. These studies contribute to the database of information available about soybean oil-based microemulsions. Hypochlorination reactions were then performed in microemulsion phases to produce hydroxylated and epoxidized soybean oil. These studies demonstrated that soybean oil can be epoxidized using hypochlorination method, and its conversion to product could be significantly increased by introduction of surfactants.; In the second part of the study, microemulsions of butyl acrylate-in-water were prepared using anionic surfactants and alcohol cosurfactants. A series of these microemulsions were photopolymerized using a two-component visible-light initiator system. NMR spectroscopy GPC studies revealed that the polymer contained diol end-groups (arising from initiator) and that the molecular weight was inversely proportional to the initiator concentration. This research illustrates the potential of microemulsion photopolymerization for the production of polymers with specified end-groups. Nearly any end-group could be imparted using this general approach since a wide variety of electron donors could be used. By imparting reactive end-groups it is possible to inexpensively construct polymers that may be used as precursors in a second reaction step. This class of architecturally controlled polymers has significant utility in important technological applications, including high performance, low-VOC acrylic thermoset coatings.