Na. Mohamed, NOVEL WHOLLY AROMATIC POLYAMIDE-HYDRAZIDES - VII - METALLIZATION OF POLYMERS THROUGH TRANSITION-METAL COMPLEXATION, European Polymer Journal, 34(3-4), 1998, pp. 387-398
Several polyamide-hydrazide (PAH)-transition metal complexes have been
prepared as metallized plastic films. The metals incorporated into th
e polymeric chains include Ag, Cu, Ni, Pb, Fe and Cd. The metallizatio
n process is achieved in three stages. The first is the complexation o
f the PAH with various transition metal salts. The second is the dopin
g of the resulting PAM-metal complex films with an ethanol solution of
iodine. The third is the reduction of the iodine-doped films with a s
odium boron hydride (NaBH4) aqueous solution. The PAM-metal complexes
have been characterized by IR, elemental analysis and UV-visible spect
rophotometry. The doping of PAM-metal complex films into an ethanol so
lution of iodine and into an NaBH4 aqueous solution was found to be es
sential for changing them from insulators to conductors. The effects o
f the dopant concentration, temperature and time of exposure on the co
nductivity of the PAM-metal complex films were studied. In all cases t
he use of a 4-6 wt% ethanol solution of iodine at room temperature for
5 min gave lower surface resistivity of the iodine-doped films, while
a 5 wt% NaBH4 aqueous solution at 65 degrees C for 1 min gave a minim
um surface resistivity in the range 10(-5-)10(-1) Ohm cm(-2). The surf
ace resistivity of these films is influenced by the type of metal inco
rporated into the polymeric chain. It decreases in the following order
: Fe > Pb > Ni > Cu > Ag. For a particular metal, the surface resistiv
ity of the films decreases with increasing metal content. Further, the
surface resistivity is affected by polymer structural variations and
is decreased by increasing the p-oriented phenylene ring content of th
e polymer. The surfaces of these films were proved to be metallized by
means of scanning electron microscopy, X-ray diffraction and electron
spectroscopy for chemical analysis (ESCA). The metallic layer generat
ed on the surfaces of the films was believed to be responsible for the
ir electrical conductivity. These metallized films maintain good mecha
nical and thermal properties. (C) 1998 Elsevier Science Ltd. All right
s reserved.