Experimental methods in chemical engineering: Barrier properties

Up to half of food spoils or goes to waste; packaging is one element that can extend shelf life and reduce the landfill burden. However, plastic packaging contributes to landfills and microparticles in the environment and, as a consequence, society has mandated industry and academics to identify sustainable materials to replace petroleum derived plastics. Oxygen, water, and CO2 permeability are among the physico-chemical properties we measure to identify the suitability of new polymer formulations. Other application of gas permeability include petroleum engineering, carbon capture, water purification, and biological systems. Here we concentrate on the basic concepts of gas transport through polymeric film as well as the effect of structural and environmental parameters. We then describe common instrumentation and data they produce with a specific focus on reference standards. To identify the major research areas, we compiled 4271 articles indexed by Web of Science since 2017 with film and polymer as keywords. The VOSViewer software tool classified the 100 most frequent keywords from these articles into six clusters: nanofilteration, thin film composites, and reverse osmosis; nanocomposites, morphology, and polyvinyl alcohol; mechanical, barrier, and physicochemical properties; permeability, membranes, and transport properties; chitosan and antimicrobial and antioxidant properties; and, films, nanoparticles, and drug delivery. Barrier property research will continue to focus on developing biobased polymers and analyzers capable of measuring multiple compounds simultaneously with dozens of samples while minimizing time.