Date of Award
Master of Science (MS)
The development and evaluation of graphene oxide (GO) coatings as a replacement for the aluminum foil layer in retort grade pouches is an important area of interest as we look to send humans to Mars. The packaging needs to not only restrict the permeation of oxygen and water vapor molecules, but also needs to be capable of thermally degrading. Compared to aluminum foil, which is responsible for the hermetic barrier properties of retort grade pouches, a GO coating is a more flexible barrier material and allows for ash-free incineration. Water-based and ethanol-based GO coatings were applied to polyethylene terephthalate (PET) and biaxially oriented nylon with Mayer rods. The weight percentage of GO in the coating and the coating weight applied to the films were varied. The adhesion, transmission rate, and incineration capability of the coated films were evaluated. The adhesion of the coatings to the films was low. Attempts were made to improve adhesion by corona treatment of the film and dilution of the coatings with isopropyl alcohol (IPA), but adhesion was not significantly improved. The oxygen transmission rate (OTR) of base PET and nylon were reduced significantly with the water based GO coating, 58% and 88% respectively. The water vapor transmission rate (WVTR) was not influenced by the GO coatings. The GO coatings did not negatively impact the film’s ability to thermally degrade, all samples had 100% weight loss. The GO coated film samples were laminated to polypropylene (PP) and the barrier properties of laminations with GO coated samples was compared to laminations with foil and other “traditional” barrier materials. The laminations were also flexed. The OTR and WVTR of the laminations with GO coated films was higher than that of the laminations with “traditional” barrier materials, but the GO laminations proved to be more flexible barrier materials as the transmission rates were not significantly impacted after flexing. Overall, the results indicate that GO coatings can be used to reduce the OTR of a material, not be negatively impacted by flexing, and fully thermally degrade.
Gibson, Michaela, "Use of Graphene Oxide Nanoplatelets as a Barrier Coating for Food Grade Packaging" (2023). All Theses. 4200.