- Diffusion coefficient of filled polymers are experimentally determined by standard water immersion test (ASTM D570). This will enable us to determine percentage increase in weight with respect to time. When percentage increase is plotted against square root of time in hours, we get a curve that has a linear and non-linear (saturation) part. From the linear part one calculates the Diffusion Coefficient by using Fick's Law. However, this requires the specimen to be immersed for a long duration of time (1-3 months or even 6 months) depending upon the barrier nature of the material.
To save time and resource is there any accelerated test ?
The parameters in the immersion test is temperature which is kept constant using water bath.
Note: By the way tests cannot be conducted at higher temperature and interpolated to lower values because the material follows different theoretical models at lower and higher temperatures.
Dear Muralishwara Kakunje, the following free access RG document reviews the different techniques. My Regards
https://www.researchgate.net/publication/317119670_Measurement_Methods_for_Solubility_and_Diffusivity_of_Gases_and_Supercritical_Fluids_in_Polymers_and_Its_Applications
Dear Muralishwara Kakunje, the following free access RG document reviews the different techniques. My Regards
https://www.researchgate.net/publication/317119670_Measurement_Methods_for_Solubility_and_Diffusivity_of_Gases_and_Supercritical_Fluids_in_Polymers_and_Its_Applications
Option 1 / In case you have access to a DVS, you can deduce the diffusion coefficient from the mass uptake rate of a thin film.
Option 2 / use the so-called wet cup test. You seal a vial with an evaporating liquid with a film of the material of interest.
1) Using reflective infrared spectroscopy
2) The type of solvent affects the mass transfer process and the diffusion coefficient
3)Investigation of diffusion coefficients
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