Enhanced Barrier Properties of High‐Density Polyethylene Using a Graphene Oxide/Boric Acid/ <scp>EVOH</scp> Composite

ABSTRACT This study examined the barrier properties of high‐density polyethylene (HDPE) against oxygen and gasoline permeation by analyzing the effects of graphene oxide concentration (ranging from 0.5 to 1.5 wt%), boric acid concentration (from 5 to 15 wt%), and the thickness of the applied surface layer on HDPE (between 20 and 40 μm). We used a Box–Behnken design within Response Surface Methodology (RSM) to determine the required number of experiments and to establish relationships between these parameters and barrier performance. To ensure uniform dispersion of the synthesized graphene oxide, we applied a multi‐stage ultrasonic technique during preparation. Additionally, the HDPE surface was pretreated with a low‐pressure cold plasma system to improve surface properties. A series of HDPE films was then produced by depositing a thin EVOH/GO/BA nanocomposite layer using a film casting machine. Contact angle analysis confirmed hydrophilization of the HDPE surface. SEM images showed the orientation of graphene oxide within the EVOH matrix. RSM plots indicated a significant reduction in oxygen permeability, falling from 120 cc/m 2 ·day·atm in neat HDPE to 1.9 cc/m 2 ·day·atm at a graphene oxide concentration of 1.5 wt%. Similarly, gasoline permeability decreased from 4.8 g/m 2 ·day·atm to 0.1 g/m 2 ·day·atm at the same graphene oxide concentration. These results indicate that the orientation of graphene oxide and its homogeneous dispersion within the nanocomposite improve barrier performance.