X-RAY, ELECTRON, AND ION-BEAM INDUCED MODIFICATIONS OF POLY(ETHER SULFONE)

The chemical modifications induced by several types of radiation on aromatic poly(ether sulfone) [poly(oxy-1,4-phenylenesulfonyl-1,4-phenylene)] have been studied by ESCA. In particular, the effects of soft X-rays (Mg K-alpha-radiation at 1253.6 eV), 1.1-keV electrons, and 1-keV Ar + and N2 + ions are compared. The following compositional effects are observed: the depletion of sulfur and oxygen with respect to carbon, and the reduction of SO2 groups to S. This is apparently the first time that the latter process has been observed in high-energy irradiation experiments. The relative importance of these two processes depends on the nature of the projectiles employed. In the case of ion bombardment both processes are enhanced. During ion bombardment the O/S ratio decreases more quickly, and the gradual destruction of the phenyl rings is also observed. On the contrary, when photon or electron beams are used, the oxygen is lost more slowly and the phenyl rings remain almost intact. A reaction mechanism for the radiation-induced reduction of the sulfonyl group is proposed on the basis of the ESCA data.