High performance metallic multilayer thin films on modified polypropylene with calcium carbonate fillers

Abstract

Metallic multilayer thin films have been successfully plated on modified polypropylene with finely dispersed calcium carbonate (CaCO 3) fillers. The peel strength of plated thin films was found to increase, mainly owing to the effect of the addition of filler rather than to the pretreatment parameters. Polypropylene moulded with 20% powdered CaCO 3 filler shows the best peel strength, reaching a maximum value 3.14 kgf cm -1, which is higher than previously reported for such metal platings. A scanning electron microscope was used to study the surface morphology of etched specimens with different filler ratios to elucidate the relationship between microstructure and peel adhesion. The mechanical bonding between metal and plastic was determined by the etched holes, whose distribution, width and depth on the surface influence the peeling strength of plated films. The ultimate peel strength was found to be attained before the surface became overetched. The advantages and wide functional applications of the newly developed multilayer metal coatings on modified polypropylene are also discussed.