Comprehensive SEC and NMR Monitoring of Monomer Functionalization for Dental Composites

Dental materials, particularly composites, require precise monomer functionalization to optimize polymerization and enhance performance. This study investigates the functionalization of triethylene glycol dimethacrylate (TEGDMA) with (3-aminopropyl)triethoxysilane (APTES) via a Michael addition reaction. The primary objective is to monitor functionalization progress and quantify monomer conversion under varying conditions. The focus is on dental composite applications, where controlled functionalization is crucial for optimal polymerization. Additionally, the study aimed to establish a broader range of reaction conditions to achieve variable monomer conversion, beneficial for diverse applications. The study explored various silane-to-monomer ratios (1:4, 1:2, 1:1, 2:1) and reaction times (2 h to 7 days) to determine optimal conversion conditions. Two analytical techniques, NMR spectroscopy and size exclusion chromatography (SEC), are used to assess functionalization and conversion. While NMR provided structural confirmation and quantification, SEC proved efficient for both qualitative and quantitative monitoring. It differentiated between single and double functionalization and accurately estimated conversion degrees, and provided accurate conversion estimates, with conversion rates reaching up to 60%. The results demonstrate that SEC is highly effective for tracking the functionalization process, offering reliable data on conversion and reaction kinetics. These findings confirm that controlling silane-to-monomer ratios and reaction time allows precise tuning of functionalization degree, which is critical for optimizing polymer properties. These findings are essential for tailoring monomer functionalization for applications beyond dental composites. The results demonstrate that SEC offers a sensitive and rapid method to monitor functionalization kinetics, complementing traditional NMR analysis. This dual-analytical approach represents a novel strategy for precisely tailoring monomer functionalization, which can significantly reduce polymerization shrinkage in dental composites and has potential applicability in other polymer systems requiring controlled functionalization.