Abstract: Graphene oxide/waterborne polyurethane acrylic (GO-WPUPA) and silane coupling treated graphene oxide/waterborne polyurethane acrylic (FGO-WPUPA) barrier coatings were prepared and then coated on the surface of poly(lactic acid) (PLA) films. An investigation on the oxygen barrier performance was conducted toward these coated PLA films. The results indicated that FGO-WPUPA coating was more effective for the improvement of oxygen barrier performance than GO-WPUPA. The addition of a small amount of FGO into WPUPA can significantly reduce the oxygen transmission rate of PLA film. When 0.5 wt % of FGO was added, the oxygen transmission rate was reduced to 234 cm3/（m2·24 h） for the film coated by 0.5 % of FGO-WPUPA coating. This resulted in a decrease by 42 % in comparation with pristine PLA film. An optimal content of FGO in the coating was determined as 1.0 wt %, and meanwhile, the optimal thickness of FGO-WPUPA barrier coating could be determined as 45 μm. With such optimal conditions, the oxygen transmission rate of the films was reduced by 51.6 % compared with pristine PLA film.

Key words: poly(lactic acid), graphene oxide, surface modification, coating, gas barrier