Structural Description of Polymer Systems in the Field of Linear Viscoelasticity

Abstract

A structural rheological model is presented, including kinetic equations of the processes of formation and destruction of aggregates of particles or associates of macromolecules. The shape of rheological curves is determined by the state of the matter’s structure and the change in the structure as a result of an oscillating shear flow. An integral characteristic of the structure is the number of meshes or contacting particles-macromolecules per unit volume. Rheological equations contain three (or two) coefficients (parameters) that have a clear physical meaning; their value is determined by the physicochemical and structural state of the system during the flow. The viscous and elastic properties of polymers are considered independently of each other. The rheological equations of the model are used to interpret the frequency dependences of the dynamic modules of some melts and polymer solutions. The existing relationship between the coefficients of rheological equations that describe viscosity, and elasticity is explained by their common structural nature.