Sorption of organic solvents by packaging materials: polyethylene terephthalate and TOPAS®

The sorption of organic solvents (1-butanol and 1-octanol) by polyethylene terephthalate and TOPAS® (cyclic olefin copolymers or COC) was investigated at 3, 23 and 42 °C and was studied by coupling two techniques (in an off-line way): supercritical fluid extraction to GC/MS. Supercritical fluid extraction (SFE) is widely perceived as a technique for the extraction of low to moderately polar compounds. The results obtained enable us to determine the corresponding diffusion coefficients and to show the relation existing between the diffusion coefficient and the following factors: the temperature, the size of diffusing molecules and the crystallinity degree of packaging materials. Therefore, the diffusions of 1-butanol and 1-octanol are less important in PET than in TOPAS® (completely amorphous).