The Modification of Polyethylene by the Thallium Sulphide Layers

Abstract

Thallium sulfide layers were formed on the surface of low-density polyethylene (PE) when the PE layer have been sulfured in a solution of higher polythionic acid H2S33O6, and then immersed in the alkaline solution of thallium (I) sulfate. Sulphur concentration increased on PE surface with the increase of the sulphurisation time. The amount of thallium in the TlxSy layers was dependent on a sulphur concentration sorbed-diffused into PE, the concentration and temperature of thallium sulfate solutions. The values of thallium content in the sulphide layer increased with increasing the duration of sulphured polyethylene treatment with Tl2SO4. Three phases TlS, Tl2S, Tl2S2 were identified by X-ray diffraction analysis in thallium sulphide layers. The data of Tl 4f7/2, O 1s and S 2p spectra showed that thallium is bonded with sulphur into TlS and Tl2S, but the Tl2SO4, S8, Tl2O3 and Tl(OH)3 are adsorbed on the layers surface too. Scanning Electron (SEM) and Atomic Force (AFM) microscopies were used to characterize surface morphology of thallium sulphide layers. The films deposited on the PE surface have a non-homogeneous structure and consist of separated islands. The process of their growth on PE surface starts from nucleation sites creating islands of TlS with a diameter in tenths of microns.