DYNAMICAL SIGNATURES OF THE VULCANIZATION TRANSITION

Dynamical properties of vulcanized polymer networks are addressed via a Rouse-type model that incorporates the effect of permanent random cr oss-links. The incoherent intermediate scattering function is computed in the sol and gel phases, and at the vulcanization transition betwee n them. At any nonzero cross-link density within the sol phase Kohlrau sch relaxation is found. The critical point is signaled by divergence of the longest time scale, and at this point the scattering function d ecays algebraically, whereas within the gel phase it acquires a time-p ersistent part identified with the gel fraction. [S0031-9007(97)04323- 8].