| Photopolymerization is most basically described as a chemical reaction whereby organic materials, exposed to radiation, combine to form high molecular weight polymer molecules. Photoinitiated polymerization has many advantages over other polymerization processes including that they are rapid, have reduced energy requirements, readily occur at room temperature, and are low cost. Another benefit is that these polymerizations are spatially and temporally controllable since the initiating light is resolvable in both space and time. An environmental benefit of photopolymerizations is that the monomer is often polymerized in bulk, eliminating the need for environmentally hazardous solvents. Finally, if multivinyl monomers are used, then crosslinking of the resulting polymer occurs, imparting unique physical properties to the product. Unfortunately, despite all of these benefits, there still exist many limitations, including oxygen inhibition and attenuated penetration of the light source into the sample.; Towards the goal of exploring one of the greatest limitations to photopolymerization, oxygen inhibition, a 1-D comprehensive photopolymerization model was developed. The model incorporates heat and mass transfer, as well as spatial profiling throughout the depth of the monomer film. Due to the spatial profiling nature of the model, the heterogeneity within the polymer film caused by oxygen inhibition was studied. Furthermore, the effect of varying polymerization parameters on the extent of oxygen inhibition was investigated. Experimental studies were conducted to investigate the degree of oxygen inhibition and the effect of varying polymerization and sample conditions. Moreover, the solubility of oxygen in monomers was investigated to better characterize the systems.; Novel monomer systems were investigated with the goal of reducing the extent of oxygen inhibition. The effect of oxygen on the photopolymerization kinetics of a novel monomer, cyclic carbonate acrylate, was studied as it is known to have unique kinetic properties that allow this monovinyl acrylate to polymerize rapidly. Additionally, the effect of adding thiol monomer to acrylate photopolymerizations was considered. Thiol concentration, functionality, and chemistry are studied, and the extent to which each affects oxygen inhibition of free-radical photopolymerizations was investigated. Finally, novel techniques to reduce the deleterious effects of oxygen were examined. |
