Introducing ASTM D3985 - Industrial Physics
ASTM D3985 is a global ASTM international standard method for measuring oxygen transmission rates through plastic films and sheeting by using a coulometric sensor.
This ASTM oxygen testing method reveals the ‘steady-state rate’ of oxygen gas transmission through a variety of plastic samples, including films, sheeting, laminates, co extrusions, or plastic-coated papers and fabrics.
The ASTM D3985 test will determine all of the following:
The oxygen transmission rate (OTR)
The permeance of the film to oxygen gas (PO2)
The oxygen permeability coefficient (P′O2) for homogeneous materials.
The ASTM D3985 oxygen testing process
To undertake a ASTM D3985 test your sample is attached to ambient atmospheric pressure as an enclosed half-block between two chambers. From here a stream of nitrogen is used to purge one chamber and oxygen is used for the other.
As the oxygen gas permeates through the film and is transferred to the coulometric detector, an electric current is generated. This is in proportion to the oxygen level streaming through the detector per unit time and the detector produces electric power in the film.
In the ASTM 3985 test oxygen is used as the test gas, while the carrier gas is nitrogen. The upper chamber oxygen gas concentration is greater than the lower chamber since some concentration difference is created between the two sides of the sample. The oxygen passes from the upper chamber into the lower chamber during the transmission process.
This isn’t the only method for OTR testing. There’s other methods of OTR inspection that use different oxygen sensors and procedures.
ASTM D3985 testing equipment
So, how can Industrial Physics improve your ASTM D3985 testing?
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