Diffusion‐controlled reaction. VI. Radiation graft polymerization of 4‐vinylpyridine to polyethylene

The radiation‐initiated graft polymerization of 4‐vinylpyridine to high‐density polyethylene was studied over a wide range of reaction conditions of radiation intensity I, monomer concentration M1, and polymer film thickness L. The conditions included both diffusion‐free and diffusion‐controlled graft polymerizations. The results corroborate our previous theoretical predictions on the effect of I, M1, and L on the experimental grafting rate. The grafting rate is inverse first order in L for diffusion‐controlled reaction and independent of L for diffusion‐free reaction. The dependence of grafting rate on radiation intensity decreases from 1/2 to 1/4 order for diffusion‐controlled reaction. Diffusion control results in a decrease in the dependence of rate on monomer concentration. The observed decrease is somewhat greater than theoretically predicted.