Adhesion improvement of polymeric substrates by the application of a copper sulfide coating

Publisher Website
Google Scholar
Abstract
A copper sulfide coating was formed on the surface of polyethylene as well as on that of plasticized polyvinyl chloride by means of consecutive treatments in sodium polysulfide and univalent copper chloride aqueous solutions. Elemental sulfur is sorbed into the polymer from the polysulfide solution, and on treating with copper chloride it turns into copper sulfide. The sulfide coating on the polymer surface consists of a continuous layer and dendrites penetrating into the polymer bulk. Both the amount of sulfide and the depth of its penetration increase both with an increase in the solubility of sulfur and the extent of its conversion to sulfide. Polymer adhesion with the sulfide coating increases with increasing penetration depth and outer surface roughness. The peel strength of the adhesive joint of the low-density polyethylene (LDPE) film without a sulfide coating was less than 0.05 kN/m and with a sulfide coating it reached 1.5-1.6 kN/m. The polymers with electroconductive sulfide coatings can be metallized using electroplating techniques. Strong adhesion can be obtained in this case without etching the polymer. The peel strength of the nickel coating on the LDPE film reached 1.2 kN/m and was as high as 10 kN/m on the plasticized polyvinyl chloride.