Abstract
We examined the synthesis of new dental resin monomers to clarify the conditions of synthesis and the properties of the monomers and bulk polymers.Octachlorocyclotetraphosphazene(4PNC)and 2-Hydroxyethylmethacrylate(HEMA)were reacted at 50℃ for 4〜100 hours, and synthesized(PNC-EMA).Of the 8Cl atoms of 4PNC, 7.72 were replaced by EMA(methacryloxyethoxy group)in 100 hours(PNC-EMA 4006).IR and XMA, revealed approximately linear relationships exist between the number of replaced EMA and the specific gravity and also the refractive index of synthesized monomers.With the increase in the number of replaced EMA, the compressive strength and the hardness(HK, HRS)of bulk polymers increased, but the transverse strength was minimum at 6.In the case of less than 6 in number of replaced EMA, the surface of bulk polymer were cracked after immersion in water at 37℃.The bulk polymer of PNC-EMA 4006, showed considerable chemical stability in water and satisfactory physical properties, with polymerization shrinkage of 9.36%, compressive and transverse strength of 4574 and 542kg/cm2 respectively, HK40.5, HRS97.2 and coefficient of thermal expansion of 66.9×10−6/℃.After immersion in water at 37℃ for 1 week, the bulk polymer of PNC-EMA 4006, the compressive and transverse strength were 3200 and 380kg/cm2 respectively, hardness was HK20.0 and HRS97.0.
