Abstract: The surface photo-oxidation and photostabilization in the photoinitiated crosslinking of polyethylene were studied using Fourier transform infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy(XPS), and the determination of gel content with irradiation time. The data show that the surface photo-oxidation of photocrosslinked polyethylene(XLPE) increases apparently with increasing UVirradiation time. The main photo-oxidation products have been identified as hydroperoxides and various carbonyl compounds. The photostabilization of XLPEcan be realized by suitable pre-irradiation using low pressure mercury(LPM) lamp or by the addition of some hindered amine light stabilizers(HALS). The optimum time of pre-irradiation by LPMlamp is 10 s under the experimental conditions in the present study. However, some HALScan reduce the efficiency of photoinitiated crosslinking process of PE.

Key words: Photocross-linked polyethylene, Surface photo-oxidation, Photostabilization, Pre-irradiation, Hindered Amine Light Stabilizers(HALS)