[Diffusion of ethylene oxide in polymer materials intended for medical use]

Kinetics of ethylene oxide desorption from medical polymers at temperatures of 25, 35 and 55 degrees C over the wide range of concentration values is studied. The content of ethylene oxide in the material has been shown to vary exponentially depending on decontaminating time. However, (formula; see text) plots have a sharp inflection which indicates the change in the mechanism of the process determining the nature of the above relationship. At the first part of the plot with great concentration values and small decontaminating time the diffusion process dominates, but at the second part (small concentrations, great time) the main process is the desorption of EO molecules the most strongly bound with polymer. Diffusion coefficients for the first degassing area are computed. The methods to predict decontaminating time are described.