Exploration of Cobalt Catalysts as Catalytic Chain Transfer Agents in Crosslinked Photopolymers

This scholarship seeks to evaluate the ability of a specific set of catalysts to alter the mechanical properties of crosslinked polymers formed with light. These catalysts will be derived from inexpensive, easily prepared cobalt species and will allow control over the material’s crosslinking density, material properties, and network topography without losing the positive effects of photopolymerization.
 

Traditionally, the free-radical polymerization of methyl-methacrylate (MMA) produces a high molecular weight poly(methyl methacrylate) (PMMA) which is further processed into very hard, transparent plastic goods (e.g. Plexiglass). In the 1970s cobalt(II) complexes were shown to greatly reduce the molecular weight of the free-radical polymerizations of various methacrylate based monomers in catalytic quantities (ppm levels) to produce high viscosity liquids. To date, this catalytic technique, frequently dubbed Catalytic Chain Transfer (CCT), has only been extended to reduce the molecular weight of linear polymeric methacrylates and has not been explored in crosslinked polymers. Here, we will investigate the ability of cobalt(II) complexes to catalytically alter the material properties of crosslinked, methacrylate-based photopolymers. We anticipate that this catalytic technique will find application in dentistry and 3D printing to create plastic goods with material properties not currently accessible with commercial formulations.