Beam Me up: Investigating Cross-Linking Behavior in Electron-Beam Polymerization of Acrylate and Methacrylate Mixtures

Electron beams (EB) are a focused stream of high-energy electrons capable of breaking bonds, thereby creating radicals and ions. These radicals and ions can participate in cross-linking reactions, which enhance thermal and physical properties by forming bonds between polymer chains. The main benefits of using EB over methods like thermal curing are its energy efficiency and the lack of solvents required. Additionally, EB does not require costly initiators, providing a significant advantage over similar techniques like UV curing. For these reasons, EB polymerization is a promising area for further investigation. The lack of specificity in EB reactions makes polymer property prediction challenging. However, control of cross-linking reactions could provide opportunities to develop advanced engineering materials. In this study, mixtures of acrylate and methacrylate monomers were investigated since they comprise industrially relevant formulations. Gel fraction was used to quantify cross-linking by measuring the mass of polymer that is not dissolved in the solvent THF compared to the original mass of the polymer sample after EB curing. Preliminary results suggest potential relationships between acrylate structure and gel fraction, though further investigation is required to establish clear trends, particularly concerning methacrylate mixtures, which have been less responsive to EB polymerization. Future research will explore the relationship between gel fraction and monomer conversion, providing insights into how these two parameters correlate. Overall, these experiments aim to enhance our understanding of the factors influencing gel fraction, with the goal of optimizing EB polymerization processes and polymer products.