Abstract
Seven types of UDMA・EDMA based photo-cure composite resins were investigated to determine the effects of the monomer structure on physical properties and dynamic viscoelastic properties.The base monomers used were mixtures of various ethyleneglycol dimethacrylates and urethane dimethacrylate(UDMA)in a molar ratio of 50/50%.And 65wt% silanized silica-fillers(1.9μm)were added to the base monomers.The results obtained were as follows.Dynamic shear modulus(G')of seven composite resins decreased with increasing temperature.As the number(n)of〓OCH_2CH_2〓_n chain of the ethyleneglycol dimethacrylates increased from 1 to 23, the G' at 37℃ decreased from 5.40GPa to 0.36GPa.The thermal expansion coefficient and water sorption increased inversely from 36.5×10-6℃ to 112.0×10-6/℃(37〜80℃)and from 0.50mg/cm^2 to 2.54mg/cm^2(30days after start of storage in water)with increases of n, respectively.
