2.3.5. Oxygen Permeability Measurements of PLA/PBAT/GR Formulations

Oxygen transition rate (OTR) values were obtained using an oxygen permeation analyzer from Systech Instruments-Model 8500 (Metrotec S.A, Lezo, Spain) at a pressure of 2.5 atm and room temperature. Films were introduced in the diffusion chamber. Pure oxygen (99.9% purity) flowed through the upper half of the sample chamber and nitrogen flowed through the lower half of the chamber. It dragged the oxygen flowing through the film and was measured by an oxygen detector. To obtain an average value of OTR per film thickness (OTR.e), three measurements were made. Thickness was measured precisely at

25 ◦C using a Digimatic Micrometer Series 293 MDC-Lite (Mitutoyo, Kanagawa, Japan) with an error of 0.001 mm. Twenty readings were taken at random positions over the 14 cm diameter circle films.
