Synthesis and Polymerization Behavior of Novel Low‐Shrinkage Hydrogel Monomers for Dental Restorative Applications

Hydrogels have potential in dental applications due to their tunable mechanical properties and biocompatibility. This study focuses on the synthesis and characterization of diacrylated polyethylene glycol (DAPEG) hydrogels with varying molecular weights as potential dental restorative materials. DAPEG hydrogels were synthesized by reacting acryloyl chloride with polyethylene glycol (PEG) of molecular weights 400, 2000, and 4000 Da using a reflux system. FTIR and 1 H‐NMR analyses confirmed successful acrylation by detecting hydroxyl group consumption and acrylate group formation. DSC revealed endothermic peaks for all cured DAPEGs. DAPEG 400 exhibited the highest gel content (96.10%) with the greatest depth of cure (3.11 mm) and degree of conversion (DoC, 86.94%). In contrast, DAPEG 2000 and DAPEG 4000 exhibited DoC of 70.39% and 54.99%, respectively, suggesting incomplete curing. DAPEG 4000 has the lowest shrinkage (1.63%), followed by DAPEG 2000 (3.94%) and DAPEG 400 (7.19%). The reduced shrinkage in high molecular weight DAPEGs was attributed to lower double bond concentrations per mole. Lower molecular weight DAPEG (400 Da) exhibits better curing properties and flowability, while higher molecular weight variants (2000 and 4000 Da) may be unsuitable for dental restorative applications due to their incomplete polymerization and high viscosity.