Multifunctional ultrahigh molecular weight polyethylene nanocomposites produced through controlled segregation of graphene nanoplatelets

We report multifunctional ultrahigh molecular weight (UHMWPE)/graphene nanoplatelet (GNP) nanocomposites with controlled GNP segregation for barrier applications. The nanocomposites were fabricated by a simple yet scalable solution mixing technique, followed by hot-press moulding, and a novel segmentation approach was used to quantify the fraction of GNP coverage on polymer granules in different concentrations ranging from 0.5 to 10 wt.%. High-resolution X-ray computed tomography (micro-CT) analysis confirmed the formation of a segregated structure. Owing to this morphology, the CO 2(g) permeability of the nanocomposites decreased by 20% with just 0.5 wt.% GNPs, with further improvement seen at higher concentrations. The well-established Nielsen model showed a good fit between the analytical and experimental permeability values. The diffusion coefficient of the nanocomposites for the solvent uptake also dropped by up to 21% compared to the neat specimens. Regarding mechanical properties, the storage and tensile moduli increased linearly with increasing GNP concentration, showing 72% and 61% increases, respectively, at 10 wt.% GNP compared to the neat UHMWPE specimens. Most importantly, the stiffness increase of the nanocomposites was accompanied by minimal loss of ductility and no additional wear loss at GNP concentrations up to 3 wt.%. In addition, the formation of a segregated network in the nanocomposites ensured a low electrical percolation threshold of 0.82 vol.%. These findings highlight the potential of these nanocomposites for multiple high-performance applications as promising candidates for per- and polyfluoroalkyl substances (PFAS)-free sealants.