Elastic properties at the sol-gel transition

We study the elasticity behaviour at the sol-gel transition with a percolat ion dynamic model via computer simulations on a square lattice. From the fl uctuations in the center-of-mass motion of the percolating cluster we deter mine the critical behaviour of the macroscopic elastic constant of the gel phase, growing above the gel point with a critical exponent mu similar or e qual to 2.7 +/- 0.1. We also study time autocorrelation functions and find that the relaxation times diverge, as the percolation threshold is approach ed from below, with a critical exponent s similar or equal to 1.9 +/- 0.1.