Diffusion Coefficients of n-Alkanes and 1-Alcohols in Polyethylene Naphthalate (PEN)

Polyethylene naphthalate (PEN) is a polyester polymer with well-known good barrier properties. PEN had been used in the food packaging area till 2012 especially as refillable bottles for soft drinks, juices, and beer. Now, PEN is mainly used in technical applications, e.g., for data storage tapes and organic light-emitting diode (OLED) applications. The aim of the study was the determination of the diffusion coefficients of organic molecules (n-alkanes, 1-alcohols) in PEN. Diffusion and partition coefficients were determined from the lag times of the permeation process of the permeants through a commercial 12 mm biaxial-oriented PEN film. In addition, activation energies of diffusion were calculated according to the Arrhenius approach. The activation energy of diffusion follows a correlation with the molecular volume of the investigated permeants. In addition, the preexponential factor follows a correlation with the activation energy of diffusion . The results of this study for PEN (e.g., , ) were compared to literature data on PET.