2.10. Oxygen Transmission Rate (OTR)

The oxygen transmission rate (OTR) was carried out on an Oxtran model 2/21 MH Mocon, Minneapolis, Minnesota, USA. The test was carried out according to ASTM D3985-17 [42] 40 h before the test. The equipment was set up at 23 °C ± 2 °C and 50% ± 10% of relative humidity. The conditions to perform the test were set up at 23 °C ± 2 °C and 50% ± 5% of relative humidity. The sample had a hexagon form of 60 mm from side to side. We determined the thickness of the sample. The sample was placed on the equipment, and Apiezon T grease was used to waterproof it. The gradient of oxygen was set up at 20 mL min⁻¹, the flow of the A, B and zero chambers were set up at 10 mL min⁻¹, and a time of three hours was considered for the retrofit; then, it takes the measures on A and B cells for 30 min. It measured the OTR of the sample for 24 h. The tests were performed in duplicate for the sample.