DETERMINATION OF THE ELASTIC-MODULUS OF SUPERABSORBENT GEL BEADS

In this paper we present a new experimental device for measuring the c ontact force and the elastic modulus of small spherical particles. We have used a system of charged poly(acrylic acid) gel beads swollen wit h brine to investigate the variation of the shear modulus as a functio n of the swelling ratio and of the cross-link degree. Although the gel modulus varies similarly to the swelling ratio power -1/3, the gel mo dulus at swelling equilibrium exhibits a strong dependence on the swel ling ratio with an exponent of -3.5. (C) 1997 Elsevier Science Limited .