FRACTAL DIMENSION OF POLYMER SORBENTS

Some methods of defining certain features that characterize polymolecu lar sorption of water vapor by polymers are discussed: the fractal dim ension, through the Frenkel-Halsey-Hill formalism; BET; the sorption f ilm area, through the Kiselev equation and the differential function o f pore surface distribution. In the framework of the BET theory, a new approach is proposed to define the surface fractal dimension of polym er sorbents, which is based on finding the number of the polylayers. T he proposed method is compared with the existing ones. The proposed de finition of the surface fractal dimension allowed to derive a three-pa rameter sorption isotherm equation, which takes into consideration the sorbent fractal properties in the domain of the relative change of wa ter vapor pressure, is 0.05 less than or equal to x less than or equal to 0.95.