The barrier properties of sustainable multiphase and multicomponent packaging materials: A review

The current packaging materials market is dominated by petrochemical-derived, single-use, and inexpensive plastics that are incredibly stable in the environment. After their sole use, only a small fraction is recycled, with the remaining ending up in landfills, incineration facilities, or littered in the environment threatening the health of our environment. Nature-derived, compostable, and biodegradable polymers are appealing alternatives to replace single-use plastics in packaging and coating applications. However, most sustainable polymer alternatives cannot compete with traditional plastics in key packaging property attributes, such as gas and moisture barrier properties. Thus, there is a dire need to design chemistries and processing technology to enhance the barrier properties of sustainable polymer systems. In this review, we conducted a critical and comprehensive summary of the important and impactful contributions on improving the gas and moisture barrier properties of sustainable polymer systems for packaging applications. The work highlights signature accomplishments on the effect of tuning the microstructure, surface energy, morphology, and self-assembly of polymers on the gas and moisture barrier properties of the resulting films and coatings. The recent developments in designing multiphase and multicomponent systems and the impact of nanotechnology on barrier properties of sustainable packaging plastics are emphasized.