Kinetic Equations for Describing the Liquid-Glass Transition in Polymers

Resumo

We present a theoretical approach based on nonequilibrium thermodynamics and used to describe the kinetics of the transition from the liquid to the glassy state (glass transition). In the framework of this approach, we construct kinetic equations describing the time and temperature evolution of the structural parameter. We discuss modifications of the equations required for taking the nonexponential, nonlinear character of the relaxation in the vitrification region into account. To describe the formation of polymer glasses, we present modified expressions for the system relaxation time. We compare the obtained results with experimental data, measurements of the polystyrene glass transition for different cooling rates using the method of differential scanning calorimetry. We discuss prospects for developing a method for describing the polymer glass transition.