Synthesis and characterization of polypyrole–SnO2 nanocomposites with study of their physical properties

Nanocomposites are a special class of materials having unique physical properties and wid application potential in diverse areas. Novel properties of nanocomposites can be obtained by the successful combination of the characteristics of parent constituents into a single material.Encapsulation of inorganic nanoparticles inside the shell of conducting polymers is the most popular and interesting aspectof nanocomposites synthesis. These materials differ from both the pure polymers and the inorganic nanoparticles in some of the physical and chemical properties. In this research a serious of nanocomposites of polypyrrole (PPy) encapsulating silica (SnO2) with nanometer size was prepared by the oxidating pyrrole with ferric chloride (FeCl3) in the presence of SnO2 nanoparticles in different dopants. The obtained compounds were characterized by Fourier-transform infrared (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques. The conductivity of nanocomposites was also investigated by four-point probe instrument. The optimum molar ratio of pyrrole:SnO2 and the best dopant with high conductivity was also found. The obtained results showed that HCl is the best dopant agent and the maximum conductivity of PPy-SnO2 is high has reached 18.02Cm-1.The size and shape of neat SnO2 nanoparticles, PPy and PPy-SnO2 nanocomposites were detrmined by SEM images. TGA results showed that the PPy-SnO2 nanocomposites have slightly higher thermal stability than neat PPy. TGA, XRD,and FT-IR data also confirmed that SnO2 nanoparticles are encapsulated by polypyrrole.