The rheological properties of polyelectrolyte cements II. Glass ionomers

The rheological properties of two glass ionomer cements, ASPA and Fuji have been investigated. The viscosities of the liquid components of these systems have been found to be Newtonian up to a shear rate of 140 s-1 with values of 0.80 N m-2 s for ASPA and 1.8 N m-2 for Fuji. Capillary viscometry techniques have been employed to study the rheological changes accompanying setting. Both cements appear to behave as power law fluids, becoming progressively dilatant as setting proceeds. The apparent viscosities of the two systems are approximately equivalent displaying values of the order of 50 N m-2 s, at a shear rate of unity shortly after mixing.