Analysis of the Gas Transport Properties of the Polyoxymethylene Copolymer: Potential for Barrier Applications

A comprehensive study of H2, CO2, O2, and N2 transport in a semicrystalline polyoxymethylene copolymer (POM-C) was conducted using the manometric time-lag method on 100 μm and 1 mm samples in the range −10 to 80 °C and 4–6 bar. Permeability, diffusivity, and solubility coefficients were determined, revealing CO2 as the most permeable gas, followed by H2, O2, and N2. The enhanced CO2 permeability is attributed to favorable interactions with the ether groups in the polymer. POM-C showed excellent hydrogen barrier performance (0.44 Barrer at 20 °C and 0.04 Barrer at −10 °C) and good CO2 barrier properties (1.6 Barrer at 20 °C and 0.215 Barrer at −10 °C). The results indicate the potential of POM-C for hydrogen and carbon dioxide storage and transport, suggesting that further investigation under higher-pressure conditions would be valuable to verify its suitability in such applications. The comparison between the two thicknesses indicates that hydrogen transport is minimally affected by the sample thermal history, whereas the other gases display moderate variations consistent with different crystallinity levels. POM-C also exhibits high CO2/O2 perm-selectivity (∼34 at 20 °C), indicating potential for packaging applications requiring controlled oxygen ingress and moderate CO2 exchange, particularly for moisture-sensitive products.