Film permeabilityThe O2 and CO2 permeabilities of the LDPE film were measuredat 20 °C by a dynamic method in a cell permeability (Davis andHuntington 1977). The film wasn’t microporous and did not containany microperforations or ventilation holes. The system consisted of2 chambers and a test film (S = 100 cm2) separated hermeticallybetween the 2 chambers. Humidified gases (100% of relative hu-midity) were flowed continuously at atmospheric pressure throughthe upper chamber. The sweep gas used in the lower chamber washelium. The flow of the permeation gas was 40 mL/mn. At steady-state, the permeated gases in the sweep gas stream were analyzedby the micro GC, and gas permeability was calculated according toFick’s law.