Preparation of EVOH/graphene oxide by blown film extrusion – correlation between film properties and graphene oxide addition

Abstract

This study reports the preparation of EVOH films reinforced with graphene oxide by twin-screw extrusion and blown film extrusion processing. The preparation of EVOH/Graphene oxide (EVOH/GO) films was carried out in two steps: EVOH with Graphene oxide powder (0-0.5 wt. %) was fed into a co-rotating twin-screw extruder, then the EVOH/GO nanocomposite was transformed into thin films using an extrusion blown film, single screw machine with 25 mm diameter and specimens test samples were obtained. The purpose of this study was to evaluate the correlation between mechanical properties and thermal stability of EVOH/GO films and the amount of graphene oxide added to the EVOH matrix. Tensile tests were conducted using an INSTRON Testing Machine. DSC and TG analysis were used for investigate the thermal stability of EVOH/Graphene oxide films. DSC analysis results showed that melting temperature (Tm), melting enthalpy (Hm) and consequently the degree of crystallinity (Xc) of neat EVOH increased with the incorporation of the 0.1 and 0.5 wt. % of GO. TG of the composites showed a great difference in weight loss and in the onset degradation temperature when compared with the neat EVOH. The more important change was observed for EVOH/GO with 0.2 wt. % GO content that presented an increase of the onset degradation temperature. A significant enhancement of the tensile strength at break of EVOH/GO flexible film without important effects on the elongation at break were also observed, except for EVOH/GO with 0.2 wt. % GO content that presented an important increase in both, tensile strength and elongation at break. It can be concluded that the addition of GO is an effective means to improve the EVOH flexible films properties and led to the obtaining of packaging materials with superior properties suitable for several industrial applications.