AbstractThe present work proposes a schematic model for predicting the water vapor transmissibility in hybrid nanocomposites based on bromobutyl (BIIR)/epichlorohydrin (CO) rubber blends. Morphology study reveals the exfoliation of nanoclay and development of hybrid nanostructures in the rubber nanocomposites. A unique correlation between water vapor transmissibility and gas (oxygen) permeability through the rubber nanocomposites has been systematically derived. The prediction of relative water vapor transmissibility was achieved by considering the polar path along with the existing tortuous path and has been validated. Interestingly, it is found that the water vapor transmissibility (TW) directly depends on the weight fraction of the polar rubber (ΦP) in the rubber blend and permeability to gas (PG) of the nanocomposites.