Food-contact epoxy resin: co-variation between migration and degree of cross-linking. Part II.
The study of epoxy resin composed of bisphenol A diglycidylether (BADGE), bisphenol F diglycidylether (BFDGE) (base), and primary aliphatic polyamines (hardener), has confirmed the interest of measuring certain physical parameters in order to evaluate the density of cross-linking of the network and thus predict the risks of resin molecules migrating into foodstuffs. This suggestion had been made in a preceding study on an epoxy resin composed of bisphenol A diglycidylether (BADGE) and primary aromatic polyamines. Samples with different densities of cross-linking, obtained by subjecting the resin to different curing temperatures (5, 20, 50 and 90 degrees C) for 7 days, were studied. The density of cross-linking increased with curing temperature, as indicated by the increase in glass transition temperature, the increased stability of the rubber storage modulus E'rub (increase in cross-link nodes), the fall in relaxation enthalpies (reduction in physical ageing) and the decreased amplitude of the loss-factor tan delta (reduction in chain mobility). Maximum cross-linking was obtained in the resin cured at 90 degrees C (temperature above Tg infinity). Concurrently, tests of migration into different liquid food simultants (distilled water, distilled water/ethanol/acetic acid, distilled water/ethanol) revealed a considerable reduction in specific migrations of BADGE and BFDGE, and of unidentified peaks.
Laboratoire de Chimie Analytique, Faculté de Pharmacie, Montpellier, France.
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C
Lambert
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Larroque
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JT
Subirats
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JF
Gérard
D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D004853:Epoxy Resins / Q000737:chemistry*; D005506:Food Contamination; D018857:Food Packaging; D006801:Humans; D011073:Polyamines; D013696:Temperature
D004853:Epoxy Resins; D011073:Polyamines