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Testing Flat Films
Preparing for a Film Test
Before a test can be conducted there are a number of tasks that must be performed: The samples to be
tested must be prepared. The samples must be mounted in a Test Cell and Loaded into the instrument.
Finally, if the test requires a Generated RH the Humidifiers must be checked and filled if necessary.
For information on preparing the film samples refer to the sections on "Sample Size", "Using Masks" and
"Orienting the Sample" in this chapter.
For information on mounting samples and loading the test cell refer to "Mounting a Sample in the Test Cell"
and "Loading and Unloading the Test Cell" in this chapter
For information on fill the Humidifiers refer to "Filling the Humidifiers" in this chapter
Sample Size
The film sample should be approximately 4" x 4" (10.16 x 10.16 cm), with a thickness not exceeding 3 mm
(0.12 inches). Smaller samples can be masked to allow them to be mounted in the Test Cell, see the
following section on "Using Masks".
The film must be cut to a specific size and shape so it will fit in the Test Cell. Mocon provides a film template
(available as part of optional Starter Kit 051-939) as an aid to cutting your film samples.
Using Masks
A foil mask should be used if any of these conditions exist:
You are testing a material with a transmission rate near or exceeding 28800 cc / (m
•
for full size samples. If such materials are tested as full size samples, the sensor will over
range.
Using a 5 cm
5 cm
2
mask will allow a sample with an un-masked (50 cm
288000 cc / (m
•
The test material is not available in pieces large enough to mount in the cell.
The test material is too fragile to support itself across the full cell area.
•
NOTE:
Some materials may fail to adhere fully to the masks, and thus give erroneous and/or highly
variable sample-to-sample transmission rates. Always check the compatibility and seal of
your sample to the mask adhesive to determine if these problems exist.
When using a mask, specify the mask open area be before starting the test. The mask reduces the area of
the test sample (from the standard unmasked 50 cm
instrument must compensate for the difference between the masked and unmasked areas.
If your sample is thin (less than 5 mils), you need only mask one side. Mount the sample in the test cell with
the film side facing up.
If your sample is thicker than 5 mils, mask both sides. Be sure the mask apertures are accurately aligned
and the edges around the foil aperture are tight against the film.
6-2
2
mask will reduce the amount of oxygen sent to the sensor by a factor of 10. A
2
• day) to be tested safely.
Revision L
OX-TRAN Model 2/12 R Operator's Manual
2
area). To correctly calculate transmission rate, the
2
area) transmission rate of up to
MOCON, Inc.
2
• day)
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