GELLED NETWORKS PREPARED FROM RIGID FRACTAL POLYMERS

Macroscopically homogeneous gelled networks, characterized by rigid rodlike polyamide segments averaging 38.5 angstrom in length connected by stiff trifunctional branch points, were prepared in a single step from fractal polymers, from monomers, and from mixtures of fractal polymers with monomers. The shear modulus, G, of the networks prepared from monomers or from the smallest fractal polymers is high and of similar magnitude. As the radius, R(H), of the fractal polymers increases, the shear modulus of the gelled networks prepared from them decreases as G-proportional-R(H)-3.3. The concentration of residual unreacted sites in the networks prepared from the smaller fractal polymers is substantially smaller than in networks prepared from the larger fractal polymers. The critical concentration for the formation of "infinite" network, C0*, is independent of the critical concentration for entanglement, C*, of the precursor fractal polymers.