Effect of boric acid on the oxygen gas barrier propertes of Poly(Vinyl Alcohol-Co-Ethylene)/Graphene oxide nanocomposite films

A facile technique that combines solution spray-coating and crosslinking method was used to prepare cross-linked composite-coated nylon films involving boric acid (BA), graphene oxide (GO) and poly(vinyl alcohol-co-ethylene) (EVOH). Accordingly, the cross-linked poly(vinyl alcohol-co-ethylene)/graphene oxide nanocomposites (EVOH/4GO/xBA) coated nylon films were prepared using BA cross-linking method to study the effect of BA towards oxygen (O₂) barrier property. In this study, borate ions, originated from BA, used as cross-linkers. The EVOH/4GO/xBA composites were prepared with a fixed amount of GO (4 wt%) and different amounts (where x = 0, 4, 8, 10, and 12 wt%) of BA with respect to EVOH. Successively, the different composite solutions were coated on modified nylon sheets at 50 °C by spray-coating technique, after that; the coated films were dried at 70 °C for 1h to fabricate O₂ barrier films. The O₂ barrier properties of all the composite-coated films increased dramatically in comparison to pure nylon sheet, and EVOH/4GO/12BA exhibited almost 83% decline in oxygen gas transmission rate (O₂GTR) compared to the pure nylon substrate. Wide angle X-ray diffraction patterns (WAXD) and fracture-sectional FESEM analyses specified that the higher oxygen barrier properties of the coated films are due to the formation of cross-linking between borate ions, GO, and EVOH. The cross-linked EVOH/4GO/xBA films could be used successfully in the field of flexible electronics (LCD and solar cells).