Effect of gamma irradiation on the oxygen barrier properties in ethyl‐vinyl acetate/ethylene‐vinyl alcohol/ethyl‐vinyl acetate multilayer film

Abstract

The potential changes of single‐use plastic materials (EVA/EVOH/EVA multilayer film in this study) used in biopharmaceutical and food‐packaging industries are investigated after several gamma irradiation doses: 30, 50, 115, and 270 kGy, and for nonsterilized samples (0 kGy) from a point of view of mechanical properties, thermal properties and permeability properties. Tensile tests, differential scanning calorimetry (DSC), oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) are performed on the multilayer film. For irradiation doses below 50 kGy, thermal and water vapor barrier properties are not altered. For higher doses (50 to 270 kGy), mechanical, thermal and water vapor barrier properties are slightly altered whereas oxygen barrier property decreases from 13 to 27 cm3.m−2.day−1. This slight change is shown not to happen due to chain entanglement or chain mobility loss in the amorphous phase of the different polymers. It rather comes from a change of the chemical environment of the EVOH layer.

Monitoring of Peroxide in Gamma Irradiated EVA Multilayer Film Using Methionine Probe

“…Model experiments ( Figure S1 ) show that over a long time, H 2 O 2 affords oxidation product and that in situ generated peracetic acid is also efficient at oxidizing, as expected [ 17 , 27 ]. Indeed, the modification of EVA/EVOH/EVA multilayer film under gamma-irradiation shows the generation of acids ( Figure 8 ), degradation of the oxygen barrier property of the EVOH layer with increasing irradiation dose, [ 28 ] and the absence of EPR signal in the EVOH layer, meaning that the generation of a large amount of H 2 O 2 is very unlikely. Thus, the in situ generation of peracetic acid ( Scheme 1 ) is not the major process leading to the oxidation of methionine ( Scheme 2 ).…”

Study of the mechanical behavior of gamma-irradiated single-use bag seals

“…The separation of these two groups is accounted for by the direction of the film extrusion. Seals 1,3 and 4 exhibit the same mechanical behavior as the EVA/EVOH/EVA multilayer film, when they are analyzed in Machine Direction (MD) mode (the direction of the polymers chains) and seals 2 and 5 exhibit the same the same mechanical behavior as the multilayer film when analyzed in Transversal Direction (TD) mode (perpendicular to the polymers chains) (Dorey et al, 2020).…”

“…For Ultimate Elongation, the film in contact with the seal shows values ~35 % lower (for both types of seal, i. e., 2,5 and 1,3,4.) (Dorey et al, 2020). Fig.…”

“…This represents the film behavior after ionizing radiation. This is explained by the fact that with gamma irradiation the chains are less flexible and they will then start to break, because of a lower tensile strength (Dorey et al, 2019;Dorey et al, 2020). Fig.…”

“…To protect their content from the external environment, these bags must be hermetically closed, meaning they must not present any opening affording contact between the solution with gas or microorganisms and they must prevent any loss of the substance they contain (Brown et al, 2000;Hron & Macák, 2013). To satisfy these criteria, plastic bags are composed of appropriate multilayer polymer films such as polyethylene/ethyl vinyl alcohol/ polyethylene (PE/EVOH/PE) or ethyl vinyl acetate/ethyl vinyl alcohol /ethyl vinyl acetate (EVA/EVOH/EVA) providing sealing and gas barrier properties (Dorey et al, 2019;Dorey et al, 2020).…”