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Evaluating organic compound migration in poly(ethylene terephthalate): a simple test with implications for polymer
1National Center for Food Safety and Technology, Illinois Institute of Technology, Summit-Argo 60501-1933, USA.
Food Additives and Contaminants
|November 1, 1996
Summary
Understanding contaminant migration in recycled plastics is crucial for food safety. This study quantizes diffusion and solubility in poly(ethylene terephthalate) (PET) to assess risks from recycled food packaging.
Area of Science:
- Food Science
- Polymer Science
- Environmental Science
Background:
- Recycled plastics in food packaging pose safety concerns due to potential contaminant migration.
- Limited data exists on diffusion and solubility of organic contaminants in poly(ethylene terephthalate) (PET).
Purpose of the Study:
- To develop and describe an approach for determining contaminant transport properties in PET.
- To quantify diffusion coefficients, permeability constants, and solubility constants for slowly migrating contaminants.
Main Methods:
- Utilized thin PET films (0.00127 cm) to create sealed packets containing model contaminants.
- Analyzed contaminant emergence in headspace (volatiles) or external liquid (non-volatiles) using GC sampling.
- Applied non-steady state and steady state diffusion equations to calculate transport parameters.
Main Results:
- Diffusion coefficients at 25°C ranged from 10⁻⁹ to <10⁻¹⁶ cm²/s.
- Observed a significant concentration-dependent increase in the diffusion coefficient of benzene.
- High permeation compounds accelerated the transport of slower permeating volatiles.
Conclusions:
- The described method effectively quantifies contaminant migration parameters in PET.
- Findings provide critical data for assessing the safety of recycled PET in food contact applications.
- Understanding contaminant transport is essential for establishing safe limits in recycled food packaging.