The Modification of Polyethylene (PE) and Polyester Textile (PES) by the Conducting Copper Sulfide Layers

Abstract

It is shown that low density polyethylene film and polyester textile can be effectively sulfurized in the solutions of
elemental rhombic (α) sulfur in carbon disulfide. The concentration of sulfur in polyethylene and polyester textile
increases with the increase of temperature and concentration of sulfur solution in carbon disulfide. However, it little
depends on the duration of treatment since the sulfur adsorption-diffusion on/into polymer takes place very fast – during
the first 3 – 5 min of sulfurization. Copper sulfide layers in the surface of polyethylene and polyester textile were formed
when these sulfurized polymeric materials were treated with the solution of copper (I–II) salts. The CuxS layers with the
lowest electrical resistance and of good adhesion with the polymer were obtained when the polyethylene was sulfurized
in the 5.7 mol/dm3 and polyester textile – in 3 mol/dm3 solution of sulfur in carbon disulfide at the temperature of 20 °C,
and when the duration of sulfurization was 1 min – 3 min. The CuxS layers of the minimal sheet resistance 11.2 Ω/ on
polyethylene and surface resistivity 102 – 104 Ω on polyester textile were formed when these sulfurized polymeric
materials were treated with copper salts solution at the temperature of 80 °C. The phase composition of CuxS layers
obtained was studied by means of potentiometric measurements and X-ray diffraction. The potentiometric measurements
showed that the values of CuxS layers electrode potentials decrease with the prolongation of sulfurized polymeric
material treatment time in the copper(I-II) salt solution at the temperature of 80 °C: from 230 mV to 145 mV – of CuxS
on polyethylene and from 212 mV to 205 mV – of CuxS on polyester textile. That indicates the change of a value of x
in the CuxS in the interval 1 < x < 2. By X-ray analysis it was determined that copper sulfide layers in the surface of
polyethylene consist of four phases: yarrowite Cu1.12S, spioncopite Cu1.4S, digenite Cu1.8S and djurleite Cu1.95S. The
copper sulfide layers on the surface of polyester textile consist of two phases: yarrowite Cu1.12S and digenite Cu1.8S.