Improvement of barrier properties of recycled thermoplastic polymers by O2 and NH2 functionalized graphene nanofillers

Graphene/polymer composites have a wide range of applications, such as energy storage, 3D printing, sensors, water purification, and heat dissipation materials due to their enhanced mechanical, electrical, and thermal properties.One major challenge is graphene's tendency to aggregate due to strong Van der Waals interactions (5.9 kJ mol⁻¹), which hinders uniform dispersion in the polymer matrix.Therefore, this study focused on improving the barrier properties of recycled polymer matrices, such as Nylon 6, Nylon 66, and polyethylene terephthalate, against moisture using chemically modified graphene nanofillers (GNPs).The nanocomposite films were prepared based on the variation of GNPs' loadings and thicknesses.The results obtained from scanning electron microscope revealed that the addition of GNPs resulted in the formation of irregular protuberances on the fracture surface of the polymer matrices, with graphene fillers dispersed within the matrices.The water vapor transmission rate (WVTR) for samples with 0.5 mm was reduced by the addition of GNPs.The moisture barrier properties of recycled polymer matrices are improved by adding O2-and NH2-to GNPs, with interfacial interactions between the fillers and the matrices dependent on the functionalization type.