| Summary: | Polyurethane is a unique polymer with excellent flexibility, elasticity, controllable hardness, fine tensile strength, abrasion and medium resistant, and stable in both low and high temperature. Since it is suitable for use as a gas barrier material, so it has a wide range of applications in fuel gas isolation, food packing, tire repairing, hot balloon, and flame retardance. The copolymerization of soft segments and hard segments formulated polyurethane, and its gas barrier properties depends on phase separation caused by two thermodynamically incompatible segments. Adjustment of molecular structure and fabrication of nano composites are effective approaches to enhance gas barrier properties. Nanoclay and graphene are widely studied as nano fillers for polyurethane, they improve the barrier ability of polyurethane to water vapor, oxygen, and carbon dioxide and other gases by blocking mechanism of which is reported to be layer stack and hydrogen bonding. In this article, mechanism of gas transport and barrier, intrinsic polyurethane, polyurethane nanocomposites is discussed. Finally, the development direction of polyurethane for gas barrier application is prospected.
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