Abstract
Mechanical properties (transverse strenght, elastic modulus and compressive strength) and water sorption characteristics of five types of urethane dimethacrylate (UDMA)-1, 6-hexamethylenglycol dimethacrylate (HMDMA) systems were evaluated under dry and wet conditions to improve the resistance of watre sorption of UDMA resin systems. The mechanical properties of each UDMA-HMDMA system showed optimum strength when the UDMA concentration was 50 to 70 mol%. The UDMA monomers containing additional phenoxy groups gave copolymers with slightly lower mechanical properties than the monomers. In the UDMA-HMDMA system, the mean water sorption was low, and the mechanical properties slightly reduced by immersion in water were comparable to those of UDMA-triethyleneglycol dimethacrylate (triEDMA) systems. These findings suggested that the employment of HMDMA as a diluent monomer would improve the resistance of water sorption of UDMA resin system.
