FROM CHEMICAL-STRUCTURE TO VISCOELASTIC PROPERTIES OF POLYMERS

The basic result of the coupling model consists of a cross-over from exp-(t/tau(o)) to exp-(t/tau*)(1-n) at a temperature insensitive microscopic time t(c). We indicate how this basic result can be derived from chaotic, interacting Hamiltonian systems which include densely packed polymer molecules. Recent quasielastic neutron scattering experiments and molecular dynamics simulations are discussed and the results are shown to support this result as well. An application of the coupling model to find how the viscoelasticity of a polymer depends on the chemical structure of the monomer through the coupling parameter of the local segmental motion is given to illustrate the utility of the model.