Surface modification of polyethylene by low keV ion beams

Ultra-high molecular-weight polyethylene (UHMWPE) and linear polyethylene ( LPE) were treated by low keV H-2(+), He+ and N-2(+) ion beams up to 2x10(17 ) ions cm(-2). and the chemical changes induced in the modified surface lay er were studied by FT-IR and XPS. The concentration of vinyl groups decreas ed, while that of the trans-vinylene, trans-trans diene, methyl and carbony l groups increased. The degree of polymer crystallinity was reduced. Change s in the valence band, in the C KVV Auger peak and in the plasmon loss spli tting of the Cls peak indicated the occurrence of graphitisation. On treatm ent by N-2(+) ions - in addition to the above changes - nitrogen incorporat ion took place. The N-content of the surface layer reached a saturation val ue of similar to 11 at% at similar to 10(17) ions cm(-2). The Nls peak was decomposed to three components at 398.3, 400 and similar to 402.8 eV, which were assigned to nitrogen in C-N, C=N (imine), and C=N with delocalised no nbonding electron pair on N, respectively. (C) 1999 Elsevier Science B.V, A ll rights reserved.