ordinarily used in rubber formulation with sulfurs are of course included in the butadiene styrene copolymer composition these additives do not constitute a novel aspect of the invention to obtain the results desired the amount of sulfur and chemical accelerator as well as multifunctional cross linking agents must be carefully controlled a typical sulfur addition is 0 5 phr and the accelerator may be present in amounts of about 0 1 phr these values may range from 0 1 to 0 8 phr for sulfur and 0 to 0 5 phr for the chemical accelerator a preferred chemical accelerator is santocure u2122 although alternative commercially available accelerators may be used a multi functional crosslinking agent must be selected to impact a moderate degree of crosslinking without interfering with the radiation curing and will therefore be selected on the basis of polymer miscibility cost and reactivity relative to sulfur and the reaction conditions a preferred agent is 3 9 divinyl 2 4 8 10 tetraoxyspiro 5 5 undecane dtud available from sigma chemical it may be used from 0 05 phr up to about 2 phr an exemplary value is about 0 1 phr those of ordinary skill in the art will select particular accelerators and crosslinking agents based on specific formulations and properties other than wear resistance crack initiation and growth resistance tear strength and ozone resistance as desired this combination is then placed in the desired mold and heated to preliminarily cure the sbr formulation under the applications of moderate heat e g about 300 u00b0 f the exposure time is about 70 minutes but may.