The Chemistry of Ultraviolet Polymerization -- Free Radical Polymerization in a Urethane Acrylate System
A majority of the chemical industry's output is polymer and plastics. The polymerization process, turning small molecules (monomers) into large ones (polymers), has four stages: initiation, propagation, chain-transfer, and termination. In my project, I am using UV light in combination with a photoinitiator to initiate the reaction. The propagation process includes the chain reaction with different monomers and oligomers in the formulation, with cross-linking occurring in the presences of multifunctional monomers. The purpose of this research is to demonstrate how physical properties of a polymer are affected by choice of monomers and oligomers in the formulation. Different monomer with varying number of functional groups or the molecular weight of different oligomers will change the final product of polymerization. To compare the different polymers, I will measure tensile strength, hardness, water absorption, depth of cure, and adhesion to different substrates. Using the same fundamental radical reaction, the choice of monomer and its functionalization leads to a variety of polymers with unique properties matching the requirements of the potential customer.