Diffusion moisture sorption by an isotropic polymer material in atmosphere with stationary and nonstationary humidity

Solutions to the Fick's diffusion equation with stationary and nonstationary boundary and nonequilibrium initial conditions for describing the moisture sorption under actual operational conditions are presented. The cases of stepwise and harmonic changes in the environmental humidity are considered. Generalized criteria for comparing the moisture sorption under nonstationary and stationary conditions are developed. A possibility of accelerated computer simulation of natural periodic changes in the atmospheric humidity is shown. The solutions obtained are approbated on a polyester resin.