CROSS-LINKS INDUCED BY SWIFT HEAVY-ION IRRADIATION IN POLYSTYRENE

The description of the cross-linking induced by irradiation with high energy ions is a difficult problem. Indeed, the cross-links are not in duced randomly as under electron or gamma irradiation: the probability to produce several events close to each others is high. Under swift i on irradiation, the production of large molecular masses directly in t he path of a single ion is favoured. We present the results obtained b y steric exclusion chromatography on the cross-linking of polystyrene irradiated with high-energy proton and carbon ions. The total cross-li nk yield and the partial yields of multiple cross-links increase with the electronic stopping power of the ion. For the highest electronic s topping power, a gel fraction can be produced directly in the track of the ion. (C) 1997 Elsevier Science B.V.