Conversion Quantification in Epoxides Annealed afte Cationic Photopolymerization

Annealing, a baking process, is widely used in industry because of its ability to improve the properties of polymer films. This research looks into comparing the effects of annealing time and temperature on light cured films made from different epoxide monomers. Each film was held at a temperature below, at, or above the polymer’s glass transition temperature for a specific time period. In addition to the various annealing temperatures and annealing times, films were annealed either immediately after polymerization, 24 hours later, or 48 hours post-polymerization. This time delay before annealing was done to determine whether dark cure occurs and how it affects the annealing process. Dark cure is commonly seen in cationically polymerizing systems, such as those containing epoxides, and can result in conversion increases in the absence of additional illumination. A differential scanning calorimeter was used to anneal the polymer, and changes in monomer conversion due to annealing were measured using Raman spectroscopy at each experimental condition. The influences of annealing on conversion for different epoxide monomers were then compared and the optimal annealing time and temperature for each monomer was determined.