Two remarkable defect related electron diffraction effects

In this note, two singular diffraction effects are reported and interpreted. For the two cases presented here, the interpretation of the diffraction pattern is only possible when combined with real space information about the defects in the material. A first observation is that of a peculiar case of so called "double" diffraction involving two crystal parts with a different structure. The second observation is that of an interference effect occuring at intergrowth structures.Dans cette note, nous présentons et interprétons deux effets remarquables de diffraction electronique. Dans les deux cas, leur interprétation n'est possible qu'en l'associant à une information obtenue dans 1'expace réel sur les défauts présents localement dans l'échantillon. Une première observation est un cas particulier de phénomène de "double" diffraction mettant en jeu deux portions cristallines de stuctures différentes. La seconde réside dans un effet interférentiel apparaissant dans des structures d'intercroissance

Determination of the nitrogen gas transmission rate (N2GTR) of ethylene vinyl alcohol copolymer, using a newly developed permeation measurement system

The oxygen (O2) barrier properties of ethylene vinyl alcohol copolymer (EVOH) have been widely investigated, but for other gases the available data are usually limited to dry conditions due to limitations in measurement equipment. Innovative permeation measurement systems with low detection limits are required to determine the gas transmission rate (GTR) of other gases, such as nitrogen (N2) at varying temperature and relative humidity. This study presents the design and development of a versatile permeation measurement system consisting of two subsystems: a permeation system and a detection system using gas chromatography and a pulsed discharge helium ionization detector. The measured O2GTR and N2GTR of three different 20 μm-EVOH grades containing 32, 44 and 48 mol% ethylene are in good accordance to those obtained on validated MOCON OX-TRAN® modules and a GC-differential pressure method respectively, with differences within the analytical uncertainty of each method

Ethylene Vinyl Alcohol Copolymer (EVOH) as a Functional Barrier against Surrogate Components Migrating from Paperboard

© 2019 Caroline Maes et al. Ethylene vinyl alcohol copolymer (EVOH) is a key material of interest as a functional barrier against substances migrating from recycled paperboard, due to its outstanding barrier properties. Three multilayer films containing two different grades of EVOH, L171B (3 μm) and F171B (3 and 5 μm), were benchmarked against a multilayer film containing polyamide 6/6.6 copolymer (PA 6/6.6, 3 μm) and monolayer polyethylene terephthalate (PET, 12 μm). The 5 films were evaluated as barrier materials against 5 surrogate substances simulating different migrants potentially present in recycled paperboard: n-heptadecane (C17) as a mineral oil-saturated hydrocarbon (MOSH), 4-methylbenzophenone (MBP) as a photoinitiator, di-n-propyl phthalate (DPP) as a plasticiser, and anthracene (ANT) and perylene (PER) as mineral oil aromatic hydrocarbons (MOAHs). The test was accelerated at 60°C for 25 days, which is equivalent to a shelf life of 2 years at 25°C. All films containing 3 or 5 μm EVOH were found to be good barriers, showing no breakthrough values over 1% of the initial concentration found in the paperboard, and they could easily compete with 12 μm PET. The multilayer with 3 μm PA 6/6.6 showed higher breakthrough values for both MBP and DPP than the other materials although still below the 1% threshold value. However, ANT showed substantial breakthrough values of nearly 2%, indicating that PA 6/6.6 might not offer enough protection against low-weight MOAH components.status: publishe

Ethylene Vinyl Alcohol Copolymer (EVOH) as a Functional Barrier against Surrogate Components Migrating from Paperboard

Ethylene vinyl alcohol copolymer (EVOH) is a key material of interest as a functional barrier against substances migrating from recycled paperboard, due to its outstanding barrier properties. Three multilayer films containing two different grades of EVOH, L171B (3 µm) and F171B (3 and 5 µm), were benchmarked against a multilayer film containing polyamide 6/6.6 copolymer (PA 6/6.6, 3 µm) and monolayer polyethylene terephthalate (PET, 12 µm). The 5 films were evaluated as barrier materials against 5 surrogate substances simulating different migrants potentially present in recycled paperboard: n-heptadecane (C17) as a mineral oil-saturated hydrocarbon (MOSH), 4-methylbenzophenone (MBP) as a photoinitiator, di-n-propyl phthalate (DPP) as a plasticiser, and anthracene (ANT) and perylene (PER) as mineral oil aromatic hydrocarbons (MOAHs). The test was accelerated at 60°C for 25 days, which is equivalent to a shelf life of 2 years at 25°C. All films containing 3 or 5 µm EVOH were found to be good barriers, showing no breakthrough values over 1% of the initial concentration found in the paperboard, and they could easily compete with 12 µm PET. The multilayer with 3 µm PA 6/6.6 showed higher breakthrough values for both MBP and DPP than the other materials although still below the 1% threshold value. However, ANT showed substantial breakthrough values of nearly 2%, indicating that PA 6/6.6 might not offer enough protection against low-weight MOAH components