Identification of chemical species created during γ‐irradiation of antioxidant used in polyethylene and polyethylene‐co‐vinyl acetate multilayer film

Abstract

With the increasing use of γ-irradiated containers made of multilayer polymeric flexible films for food and biopharmaceutical applications, the possible migration of degradation products of the polymers and their additives is becoming a topic of concern. This article aims at highly reliably identifying the degradation products generated after gamma irradiation and their origin to later on assess their potential harmfulness in single-use containers. In this study, GC-MS is used to identify by-products created by γ-irradiation of primary and secondary antioxidants usually present in polyolefin-based biotechnological single-use materials and to confirm identification relevancy based on the literature survey or standard when available. Degradation pathways are proposed to account for the formation of by-products identified during the study and to list intermediates and other by-products present in too small amounts to be detected and identified accurately in all extractable studies.

Influence of Gamma Irradiation on Electric Cables Models: Study of Additive Effects by Mid-Infrared Spectroscopy

“…This phenolic antioxidant inhibits the propagation of free radicals that are stabilized by its aromatic cycle [ 31 ]. The degradation pathways of this additive are complex and numerous as explained by Dorey and et al [ 16 ]. The many degradation products result in a spectrum with no clearly identifiable bands except for those of the XLPE polymer, which seems to be protected by the additive.…”

“…The degradation could be observed in terms of formation of radicals [ 8 ], small molecules, inter- and intra-chain bonding, unsaturations, colorings [ 9 ] and formation of oxidized molecules [ 10 , 11 ], resulting in crosslinking and/or chain scission [ 12 , 13 ] which could alter the mechanical properties of the material [ 14 , 15 ]. The degradation of additives is also commonly observed [ 16 , 17 ]. These modifications depend on polymer formulation, gamma dose, dose rates and ageing post irradiation [ 18 , 19 ].…”

Ageing evaluation of cable insulations subjected to radiation ageing: Application of principal component analyses to Fourier Transform Infra‐Red and dielectric spectroscopy

“…This trend is expected since no external stabilizers (e.g., AOs) are present inside the polymeric compound as seen in [43,44]. The absence of additional stabilizers allows the oxidative reactions to freely take place according to the well-known reaction scheme reported, for example, in [34,45]. The degradation products arising with ageing are just given by the oxidation of the main polymer chain by substituting hydrogen atoms with oxidised groups, for example, ketones and carboxyl acids, as seen for the FTIR analyses.…”

“…The observations performed on Mod2 highlight the consumption of Irganox 1076 during gamma irradiation. Dorey et al [34] described the complex formation mechanisms leading to degradation products, which results into an IR spectrum with hardly identifiable bands except for the ones of XLPE. The observations made on Mod3 suggest a significant chemical consumption of Irganox PS 802 during gamma irradiation.…”

Investigations at the Product, Macromolecular, and Molecular Level of the Physical and Chemical Properties of a γ-Irradiated Multilayer EVA/EVOH/EVA Film: Comprehensive Analysis and Mechanistic Insights

“…This EVA/EVOH/EVA multi-layer film was investigated using several techniques: Fourier Transform InfraRed (FTIR) spectroscopy [ 28 ], Electron Paramagnetic Resonance (EPR) [ 29 ], colorimetry measurements [ 30 ], HPLC to measure the oxidation event [ 31 ] pH, conductivity, Total Organic Carbon (TOC), ion chromatography [ 32 ], X-ray Photoelectron Spectroscopy (XPS) [ 33 ], tensile tests, Differential Scanning Calorimetry (DSC), Oxygen Transmission Rate (OTR), and Water Vapor Transmission Rate (WVTR) [ 34 ]. All these techniques generated a large amount of data, which were analyzed using chemometrics methods such as Principal Component Analysis (PCA) [ 35 ] and ANOVA Common Dimensions (AComDim, Analysis of Variance in Common Dimensions) [ 36 ].…”