Penetrant Transport in Semicrystalline Vs. Amorphous Poly(ethylene furanoate)

Poly(ethylene furanoate) (PEF) has emerged as an attractive alternative to poly(ethylene terephthalate) (PET) for beverage packaging applications due to biological sourcing and significantly improved barrier properties for O₂ (11X), CO₂ (19X) and H₂O (2X). Prior fundamental work has focused only on characterizing the transport properties of amorphous PEF; however, real-world beverage container applications involve complicating factors such as orientation and crystallinity. The current work extends our prior transport studies for amorphous PEF to investigate semicrystalline PEF prepared via isothermal crystallization at two temperatures. Permeation and pressure-decay sorption methods are used to examine the transport properties of O₂ and CO₂, while a gravimetric sorption technique enabled measurement of the sorption and diffusion properties of H₂O. Density and differential scanning calorimetry techniques provided estimates for the percent crystallinity of the samples. The corresponding transport data for these semicrystalline PEF samples will be examined to check for consistency with the two-phase model of crystallinity.