Objectives: The purpose of this study was to develop a heat-cured resin with improved toughness. Polyurethane dimethacrylate (PUDMA) with hard and soft segments in the chemical structure was synthesized using polyurethane diisocyanate and 2-HEMA.
Methods: The bulk polymerization of PUDMA, Bis-GMA, TEGDMA and MMA was carried out in a glass tube with 0.5 wt% of BPO at 60 degrees C for 24 h and 110 degrees C for 3 h. The physical and mechanical properties of these polymers were measured, i.e., the polymerization shrinkage, water sorption, transverse strength, modulus of elasticity, deflection and Knoop hardness of these polymerized methacrylates were determined.
Results: The volume shrinkage and the water sorption values of PUDMA were lower than those of Bis-GMA. The transverse strength and the modulus of elasticity of PUDMA were close to those of PMMA. The deflection of PUDMA, as determined by a bending test, was higher than any of the other cured resins tested.
Significance: These results suggest that PUDMA is an excellent toughened polymer. The fracture toughness of PUDMA is sufficient for crown and bridge resins and dental composites.