Property improvements of EVOH by enhancing the hydrogen bonding

Abstract

Ethylene-vinyl alcohol (EVOH) with excellent barrier properties is insufficient in mechanical properties, which limits its application. For the purpose of enhancing mechanical properties of EVOH, blend of anhydrous magnesium chloride (MgCl 2 ) with EVOH was prepared by melt blending. Enhanced hydrogen bonding can be achieved through interaction between the Cl of MgCl 2 and -OH in EVOH, and the stronger hydrogen bonding between MgCl 2 and EVOH was confirmed by using Fourier transform infrared spectrometer and X-ray photoelectron spectroscopy. The chemical, thermal and mechanical properties were evaluated. The thermal analysis of blends demonstrated that the melting temperature (T m ), the crystallisation temperature (T c ) and the crystallinity were effectively decreased with adding MgCl 2 , on the contrary, the glass transition (T g ) was significantly increased from 42.8 to 77.5°C. The mechanical test results revealed that MgCl 2 can significantly improve the storage modulus and the viscosity of EVOH, also the tensile strength was raised by nearly 30%.

Solid polymer nanocomposite electrolytes based on poly(ε‐caprolactone)‐based waterborne polyurethane–polyethylene oxide and fluorine‐doped carbon quantum dot‐MXene

“…However, for $$$ T>{T}_{m, PEO} $$$, the higher $$$ {E}^{\prime } $$$ values could only be related to the hydrogen bonding in the blends. Studies on the hydrogen bonding at high temperatures suggest that this interaction exists even at 200$$$ {}^{{}^{\circ}}\mathrm{C} $$$ in the form of dynamic hydrogen bonding between OH groups and electronegative atoms and functional groups 43,44 . Therefore, it can be safely assumed that the hydrogen bonding is responsible for the high‐structural stability of the blends.…”

“…42 However, suppressing the crystallization process comes with a cost and that is usually OH groups and electronegative atoms and functional groups. 43,44 Therefore, it can be safely assumed that the hydrogen bonding is responsible for the high-structural stability of the blends.…”

The High-Performance Polymer Electrolytes Based on Agarose–Mg(ClO4)2 for Application in Electrochemical Energy Storage Devices

“…The smallest crystallite size recorded at 30-Mg(ClO4)2 proves the reduction of crystalline nature after the participation of salt in the polymer matrix. At this concentration, the crystalline peak becomes broader and lower in intensity, thus exhibiting the lowest degree of crystallinity, about 27.39%, resulting in the system's highest amorphous nature, promoting the transportation of ions in the polymer matrix [20,38]. Beyond this concentration, the degree of crystallinity is observed to become increase.…”

Impact of Magnesium Salt on the Mechanical and Thermal Properties of Poly(vinyl alcohol)

“…Several advanced studies on the effect of salts on polar polymers have been reported recently. Such polymers include ethylene-vinyl alcohol [13], bisphenol-A polycarbonate [14], poly(lactic acid) [15], polyamide 6 [16,17], poly(methyl methacrylate) [18][19][20][21], and a copolymer of vinyl butyral and vinyl alcohol [21]. Studies have revealed that the mechanical properties of these polymers are improved by the addition of a salt.…”

“…Although lithium salts have been investigated greatly as mentioned, we focused on magnesium salts for the following reasons: (1) Magnesium salts have the smallest cations and the largest lattice energies; they form the strongest and most stable ionic bonds. This contributes to the formation of strong ion-dipole interactions with PVA chains [13]. In general, the main factor that influences the lattice energy of ionic crystals is ionic charge.…”