We report here special features of mechanochemical reaction of plasma-irradiated polyethylene (PE), low density PE (LDPE) and high density PE (HDPE). A dangling bond site (DBS) of three component radicals formed on a PE surface by argon plasma-irradiation disappears rapidly by mechanical vibration with a Teflon twin-shell blender, causing successively solid state radical recombination reaction. When mechanical vibration of plasma-irradiated PE is similarly conducted together with a powdered drug, the sustained release powders are obtained due to trapping of drugs into the powder matrix formed by mechanochemical solid state recombination of plasma-induced PE surface radicals.