الفهرس 
Introduction and aim of the workOnly 14 pages are availabe for public view
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Abstract
The goal of the present wok is to synthesize, characterize and study the electrical properties of conducting polymeric composites. Polypyrrole (PPY) is one of the most attractive polymers to come from a new class of materials that have potential technological applications. Futher research explores a method of combining PPY with other polymers. Ploypyrrole – based composites were prepared by soaking polymer matrix in pyrrole monomer followed by immersing in aqueous solution of ferric chloride. Among the different polymer matrices used, ethylene viny1 alcohol copolymer (PEVA) with 68 mol.% PVA has received the most attention as a host polymer. This is because of its high mechanical properties and crystallinity. The effect of synthesis conditions on the morphology and electrical properties of the chemically oxidized conducting composites was investigated.
Characterization methods such as scanning electron microscope (SEM), UV-absorption , FT-IR spectroscopy and wide angle X-ray diffraction, (WAXD) have proved the location of the pyrrole molecules in the intercrystalline voids (amorphous regions) of the host polymer. This indicates that the conductive paths of PPY can be generated uniformly over the molecular chain gaps of PEVA copolymer. Therefore, the surfaces of the semi-crystalline film are well coated by highly conductive PPy layers and a continuous PPY network is established within the amorphous regions. The thermal stability of the conductivity to ambient air exposure is satisfactory.
DC conductivity of the composite films was investigated in the temperature range from 193 to 373K. It was found that the electrical properties could be varied systemically by increasing the PPY content. The dependence of the conductivity on the temperature follows a mixed ”mode” of conduction. This finding has been explained on the basis of a phase-segregated morphology having highly conducting domains separated by a semi-conducting / insulating matrix.
Measurements of AC conductivity in the temperature range 187-373K were carried out. The AC conductivity is shown, depending on the PPY content, to follow the general law σ = Aωs in low temperature region 187 K and for higher frequencies (> 10HZ).
The response of the conducting composites to UV irradiation has been investigated. During UV illumination, the conductivity increases slowly till reaches an equilibrium value. After UV was switched off, the conductivity decays and its value becomes nearly equal to the initial (dark) value.