ASTM D3985

OTR Oxygen Transmission Rate | ASTM D3985

Oxygen Permeation of Flexible Barrier Materials Using a Coulometric Sensor ASTM D3985, ISO 15105

ASTM D3985 - Standard Test Method for Oxygen Gas Transmission Rate Through Plastic Film and Sheeting Using a Coulometric Sensor

ASTM D3985 Application Fields:

This test method covers a procedure for determination of the steady-state rate of transmission of oxygen gas through plastics in the form of film, sheeting, laminates, coextrusions, or plastic-coated papers or fabrics. It only applies to oxygen permeability testing of specimen under drying condition(Relative moisture less than1% RH ). Test performed under wet condition can refer to ASTM F 1927. Oxygen permeability of most film will vary greatly with the changing of humidity.

ASTM D3985 Testing Method:

The specimen is mounted as a sealed semi-barrier between two chambers at ambient atmospheric pressure. One chamber is slowly purged by a stream of nitrogen and the other chamber contains oxygen. As oxygen gas permeates through the film into the nitrogen carrier gas, it is transported to the coulometric detector where it produces an electrical current, the magnitude of which is proportional to the amount of oxygen flowing into the detector per unit time. Among that, oxygen gas is the testing gas and nitrogen gas is the carrier gas. Oxygen gas concentration of upper chamber is higher than that of lower chamber, due to which certain concentration difference is formed between both sides of specimen. During the transmission process, oxygen gas transmits from upper chamber through specimen into lower chamber.

ASTM D3985 is the commonly used standard for film oxygen permeability testing using oxygen sensor at present. Temperature and humidity are critical parameters influencing final test data. That is why efficiency controlling of testing environment is a way to improve testing accuracy.