A semi-empirical model has been developed for additive diffusion in po
lymers. The model estimates apparent diffusion coefficients of an addi
tive migrating through polyolefin polymers into a fatty food simulant
for a range of temperatures between the glass transition and melting t
emperatures of the polymer. This diffusion model has been applied to s
everal additive/polyolefin systems to determine its validity and limit
ations.