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8311500 
Journal Article 
DETERMINATION OF DIFFUSION COEFFICIENTS OF ANTIOXIDANTS IN POLYETHYLENE BY GAS CHROMATOGRAPHY 
Braun, JM; Poos, S; Guillet, JE 
1976 
14 
5 
257-261 
The efficacy of stabilizers in bulk polymers is often related to the ability of the stabilizer molecule to diffuse to a reactive site. Antioxidants, for example, are known to react with free-radical intermediates to reduce the efficiency of the radial chain oxidation process in hydrocarbon polymers. The rates of such reactions must bear some relation to the diffusion coefficients of both the radical intermediates and the antioxidant molecules in the polymer medium. In this paper the authors report a simple method for determining the approximate values of such diffusion constants, illustrated by the measurement of diffusion of the stabilizers 3-tert-butyl-4-hydroxyanisole (BHA) and 3,5-di-tert-butyl-4-hydroxytoluene (BHT) in low-density PE. Measurements were also made on the diffusion of n-dodecane, tetralin and cis- and trans-decalin for comparison. Experimental results are presented and evaluated with the use of mathematical equations derived for diffusion coefficient calculations.