Gas barrier properties evaluation for boron nitride nanosheets-polymer (polyethylene-terephthalate) composites

Hexagonal boron nitride nanosheets (BNNS) are dispersed in polyethylene-terephthalate (PET) via temperature-induced solution processing. The BNNS/PET composites are evaluated for carbon dioxide (CO₂) and oxygen (O₂) permeation reduction. The free-standing composite membranes have shown a maximum 96% permeation reduction at very minute filler loading (0.005 wt% BNNS) in comparison to the base polymer when subjected to an 8 h test run. Interestingly, BNNS loading beyond 0.005 wt% rendered complete permeation reduction. The inclusion of high aspect ratio BNNS, homogeneous dispersion inside PET and the wiggling effect around nanosheets per flake have increased the tortuous path for the gas flow. The experimental results have been verified through Bharadwaj’s, Neilson’s, Lape’s and Cussler’s models. The dispersion state is assessed via scanning electron microscope (SEM) while x-ray diffraction (XRD) has confirmed the formation of composites. Tensile testing results showed the enhanced mechanical robustness of BNNS/PET composites as a function of filler loading.