Tests for Permeability Properties

Water-Vapor Transmission. Primary Film Test Method ASTM E96. The primary test method for the determination of water-vapor transmission through plastics less than 32 mm thick is ASTM E96. (See Fig. 4.) There are two basic methods the Desiccant Method and the Water Method. Agreement between the two methods should not be expected. The method selected should be the one which most nearly approaches the conditions of use. 

The film sample specimen, 64 mm square, is attached to a sled. The second surface, 254 mm x 127 mm, remains fixed as the sled is pulled across at a controlled rate. The frictional force is measured by a stream gauge.fi ]  

Folding Endurance of Paper by the M.I.T. Tester. Primary Film Test Method ASTM D2176. The folding endurance test is used for determining the folding endurance of paper and plastic by use of the M.I.T. tester. It is recommended for papers/films less than 0.25 mm. This test method is the technical equivalent of TAPPI T511. 

Bursting Strength of Paper. Primary Film Test Method ASTM D774 Additional Test Methods ISO 2758 and TAPPI 403. The test 

The WVTR is reported as grams of water which will pass through a given area of the material in a specified time. 

---