Structure-property relationships for novel wholly aromatic polyamide-hydrazides containing various proportions of para-phenylene and meta-phenylene units-V:: Evaluation of the electrical surface conductivity of several metallized plastic films

Electrical conductivities of several metallized polyamide-hydrazide films have been investigated. These metallized plastic films were prepared by reduction of the corresponding polyamide-hydrazide-transition metal complex films using sodium boron hydride (NaBH4). The metals incorporated into the polymeric chains include silver, copper, and cobalt. The effect of NaBH4 concentration, temperature and time of exposure on the conductivity of the polyamide-hydrazide-metal complex films has been studied. The optimum effect was attained using 4-6 wt% of NaBH4 aqueous solution for about 2-3 min exposure at 60-80 degrees C. The electrical resistivities are in the range of 10(-6-)10(3) Omega cm(-2), and are influenced by the type of metal incorporated into the polymeric chains. They decrease in the following order: Co > Cu > Ag. For a particular metal, the surface re sistivity of the films decreases with increasing metal content. The metallic layer generated on the surfaces 6of the films upon reduction was believed to be responsible for their electrical conductivity. Moreover, the surface resistivity is also affected by polymer structural variations and is decreased by increasing para-oriented phenylene ring content of the polymer. The metallized films showed good environmental stability. (C) 2007 Elsevier Ltd. All rights reserved.