Effect of impurities on polyethylene adhesion

The peeling strength of an aluminium foil glued to a glass plate with ‘adhesionable’ polyethylene was lowered by incorporating oleic acid into polyethylene. The average thickness τ of the organic film remaining on the aluminium after peeling was a few microns for pure polyethylene, near 20 μ for a mixture of polyethylene 99.6 and oleic acid 0.4 parts, and very small (for instance, 0.5 μ) for a mixture of polyethylene 97 and oleic acid 3 parts. In grossly contaminated polyethylenes, rupture occurred in a weak boundary layer and τ depended on location and extent of these layers.