Direct measurement of additive migration from low-density polyethylene as a function of space and time
Centraal Instituut voor Voedingsonderzoek TNO
A method, based on microtoming and GC analysis, for studying migration of additives inside polymers as a function of space and time was validated for Irganox 1076 migrating from low-density polyethylene to ethanol. The consistency of the mass balance of the total amount of Irganox 1076 in the polymer and the solvent after different incubation times was acceptable considering errors introduced by the analytical procedure. A solution of Fick diffusion equations, fitted to concentration profiles inside the polymer at different incubation times, was found to describe well the transport process as a function of both position and time with a diffusion coefficient of 1.1 × 10-13 m2 s-1. This value corresponded to the diffusion coefficient obtained using conventional measurements of an Irganox 1076 concentration in ethanol as a function of time. Compared to a stationary solvent, no significant effect was observed on the diffusion coefficient by gently shaking the ethanol. Diffusion coefficients measured at different temperatures using the validated method followed an Arrhenius type of relationship with an activation energy of 113 kJ mol-1 Conclusively, the method was found to be well suitable for studying additive migration in polymers as a function of both space and time. © 2002 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 86.
To reference this document use:
Journal of Applied Polymer Science, 86 (12), 3185-3190