DETERMINATION OF DIFFUSION-COEFFICIENTS OF GASES THROUGH A FLAT POLYMERIC MEMBRANE BY THE METHOD OF NONLINEAR-REGRESSION

Non-linear regression was applied for calculation of diffusion coeffic ients of gases through a flat polymeric membrane from the experimental data obtained by the flow permeation method with the thermal conducti vity detection of composition of gaseous mixture. To verify this metho d a polyethylene and carbon dioxide was chosen. Diffusion coefficients of carbon dioxide in the low-density polyethylene of two different th ickness at the temperature of 25-degrees-C were determined with precis ion about +/- 2.5% in agreement with literature.