Polyamide grafting onto ethylene-vinyl alcohol copolymer

Abstract

Ethylene-vinyl alcohol copolymers (EVOH), with appropriate barriers and processability, can be chemically modified through vinyl alcohol units. Amides and polyamides based on condensation reactions of adipoyl chloride and hexamethylenediamine were grafted onto EVOH. Grafting was characterized by contact angle measurement, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), nuclear magnetic resonance spectroscopy (NMR) and scanning electron microscopy (SEM). Amide peaks at 3302 cm -1 corresponding to -NH bond stretching and the absorption of HN-CH 2 at 7.8 ppm, were observed from ATR-FTIR and NMR, respectively, as a result of grafting. SEM showed the formation of amide structures as bundles, agglomerates and needle-like particles. Differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) showed considerable changes in onset of melt temperature, crystallinity and various transitions in grafted EVOH, showing an effective alteration in the physical properties compared with the virgin resin. Nylon grafted EVOH can be considered as a potential compatibilizer in polyethylene (PE)/polyamide blends via increasing interactions at the interface.

Freshness Traffic Light for Fish Products: Dual-Optode Label to Monitor Fish Spoilage in Sales Packages

“…The EVOH copolymer is a commercial plastic material commonly employed as a gas barrier layer in polylaminate packaging. − ,− It is transparent, biocompatible, and insoluble in water, and it shows good mechanical and thermal properties and processability. , From a chemical point of view, it consists of a unique copolymer of ethylene and vinyl alcohol that can be easily functionalized with various molecules to obtain advanced materials for various applications. − In Figure S1, the chemical structure of EVOH and the commercial EVOH beads are shown.…”

Chemometric-Assisted Litmus Test: One Single Sensing Platform Adapted from 1–13 to Narrow pH Ranges

“…Looking back to the history of this kind of device and keeping in mind the still-open issues in this field, we propose our chemometric-assisted litmus test (CLT), a reversible, accurate, and tunable sensing platform composed of 3 × 4 miniaturized colorimetric sensors covering pH measurements in an extensive range from 1 to 13. These miniaturized colorimetric sensors are prepared by covalent functionalization of commercially available pH indicators to the ethylene vinyl alcohol (EVOH) copolymer, a plastic-based material used in food packaging with interesting features for application in the sensor field such as transparency, water insolubility, processability, and film-forming ability by pressing or extrusion [ 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. Reversibility is achieved thanks to the combination of covalent immobilization and pH-sensing by classical protonation and deprotonation reactions of pH indicators; meanwhile, the multivariate data treatment, relying on RGB extraction from images and their analysis by chemometric tools such as principal component analysis (PCA) and partial least square regression (PLS) [ 36 , 37 , 38 , 39 ] allows for an accurate measurement of pH value with no need of any instrumentation apart from a common smartphone or a camera [ 37 , 40 ].…”

DFO@EVOH and 3,4-HP@EVOH: Towards New Polymeric Sorbents for Iron(III)

“…In the present research, we explore the possible use of ethylene-vinyl alcohol copolymer, EVOH, as a support to obtain an extrudable material, which, in principle, is much more convenient for a practical application thanks to its ability to be dissolved in hydro-alcoholic mixtures and applied by coating or printing procedures on flexible substrates [19][20][21][22][23].…”