Determination and Prediction of the Lag Times of Hydrocarbons through a Polyethylene Terephthalate Film

Abstract

Polymeric materials can be used as functional barriers to prevent contamination of food from the environment or from other packaging components, e.g. mineral oil hydrocarbons from printing inks. Polyethylene terephthalate (PET) is such a promising barrier material. From permeation studies found in the scientific literature lag times, diffusion coefficients or permeation rates towards organic chemicals could not derived because of the slow diffusion process of the permeants in PET. Knowledge about lag times or diffusion coefficients for different permeants, however, is essential for the evaluation of the barrier properties of PET films towards organic contaminants, e.g. mineral oil hydrocarbons.The aim of the study was to develop automated permeation testing method in order to determine the lag times of high-barrier films. From the lag times, the diffusion coefficients as well as the partition coefficients of the alkanes were calculated. In addition, the permeated amounts were simulated by use of diffusion models. Therefore, the lag times can be predicted under different experimental conditions as used in the current study. The results of this study show that the investigated 12 μm PET film is an effective barrier towards mineral oil hydrocarbons. For example, the predicted lag time for n-octane or n-dodecane at 40°C is 8.8 and 210 years respectively.

Functional Barrier Performance of a Polyamide-6 Membrane Towards n -Alkanes and 1-Alcohols

“…The partition coefficient can be derived from the slope of the asymptote according to Equation 2. 13 The factor A within this equation is the area (typically expressed in cm 2 ) whereas I (in cm) is the thickness of the tested polyamide membrane. The upstream concentration of the permeant in the permeation cell is c gas phase ( Table 1).…”

“…Therefore the barrier performance of various packaging films has been investigated recently. [11][12][13][14][15] Following these studies, polyamide-6 (PA6) as well as polyethylene terephthalate (PET) used as inner liners of cardboard containers showed very good barrier properties towards mineral oil contamination. For example, Fiselier and Grob 11 reported that 20 μm PA (cast) as well as 12 μm PET films show good barrier properties towards MOSH and MOAH.…”

“…The use of functional barriers seem to be a practical way to reduce the contamination of MOSH, MOAH and other contaminants in cardboard packed food. Therefore the barrier performance of various packaging films has been investigated recently . Following these studies, polyamide‐6 (PA6) as well as polyethylene terephthalate (PET) used as inner liners of cardboard containers showed very good barrier properties towards mineral oil contamination.…”

“…In our previous study, the lag times of PET were determined for n-alkanes between 70°C and 120°C by use of a high temperature permeation method. 13 The same methodology can be used for the determination of the diffusion and partition coefficients of PA6 films.…”

Development and evaluation of organic vapour permeation system for packaging applications

“…The permeation curves were found to be very similar with results of Apostolopoulos and Winters, indicating that a high concentration gradient of organic vapours increased the rate of diffusion and had much shorter lag time, thereby allowing the system to reach equilibrium even faster. The method applied by Ewender and Welle was able to simulate the permeation rates by use of diffusion modelling, which determined the lag times for n‐alkanes through high‐barrier PET films. This study showed that the investigated PET film had good barrier properties toward organic contaminants.…”