A mathematical model of mass transfer from lamina (plant leaf) into the extractant is constructed considering its anatomical organization in particular the existence of cellular and intercellular space. Its solution allows to predict kinetics of the extraction process of the whole leaves at its implementation in practice.
We present results of development of mathematical models of external mass exchange in extraction of desired products from vegetable raw materials and mathematical models for the determination of the minimum time of achievement of the equilibrium state of the system and the current concentration of a soluble substance for their using in the optimization of operation of solid-phase extraction equipment.
The kinetics of controlled release of medicinal substances from chitosan films has been investigated. Correlation between values of diffusion coefficients and the sedate indicator characterizing diffusion of medicinal substance from a film and shares of medicinal substance connected with a polymeric chain has been established. With the increase in amount of the entered medicinal substance the rate of release of medicines decreases.
The structure of extruded films based on blends of polyvinyl alcohol and poly(3-hydroxybutyrate) (PHB) was studied for various compositions. The methods of DSC and X-ray analysis were used. As the phase-sensitive characteristics of the composite films, diffusion and water vapor permeability were also investigated. In addition, the tensile modulus and relative elongation-at-break were measured. Changes in the glass transition temperature of the blends and constant melting points of the components show their partial compatibility in intercrystallite regions.