抄録
A statistical mechanical theory of steady viscosity in bulk polymers is presented. In slowly relaxing phenomena such as steady viscosity, the inter-chain relaxation is predominant and the segmental conformation of each polymer molecule attains to a state of dynamic equilibrium. It is assumed that the intermolecular force between two molecules consists of two parts: the force derived from potential and the friction due to entanglements between them. The general expression of viscosity is derived from the fundamental equation for the velocity distribution function of a polymer molecule, using Born-Green’s method.
The molecular weight dependence of viscosity η is roughly estimated by taking into account the inner structure and conformation of polymer molecules. The result is η=C1N+C2N3, where N is the number of segments constituting a polymer molecule, C1 and C2 are constants, and C1>>C2. This prediction agrees semi-quantitatively with experiment.
