Studies on Denture Base Resins : Part III Dynamic Shear Modulus in Torsion Sulfone Resins

Abstract

The dynamic shear moduli of 5 types of denture base resins, two acrylic resins(heat-cured resin and fluid resin), polycarbonate resin, polysulfone resin and polyethersulfone resin were measured using a torsion pendulum viscoelastometer at a temperature between 23 and 200℃.For sulfone resins(polysulfone resin and polyethersulfone resin), the shear moduli at 37℃ were nearly 1×10¹⁰dyne/cm², which were lower than those of acrylic resins.In spite of the increasing temperature, the shear moduli were markedly stable.Though peaks in the loss tangent were observed at 80℃ and 160℃, the values for the loss tangent were lower in comparison with those of other materials.This shows that sulfone resins are fairly tough.The slightly lower modulus for the specimen containing water indicates that the presence of water has little effect on the shear modulus of sulfone resins.