Synthesis and characterization of nanocomposites consisting of polyaniline, chitosan and tin dioxide

Polymeric nanocomposites composed of polyaniline (PANI)/tin dioxide (SnO2), and PANI/chitosan(CS)/SnO2 were synthesized chemically by in situ polymerization method. The aniline polymerization was carried out using DBSA as protonating agent, and APS as oxidizing agent. The tin dioxide nanoparticles dissolved in hydrochloric acid (HCl) was added during the synthesis process. Nanocomposites were examined by X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetry (TGA), Fourier transform infrared spectroscopy (FTIR), photoelectrons excited by X-rays (XPS), and Mössbauer (EM). The results of XRD pattern indicate that nanocomposites are crystalline due to the presence of SnO2 nanoparticles with reflection planes corresponding to the tetragonal rutile structure. XPS and FTIR results reveal that the protonation degree of PANI/CS/SnO2 sample is higher than that of the PANI/SnO2 and pure emeraldine salt PANI samples. These results suggest that the conductivity would be much larger in the PANI/CS/SnO2 sample. TGA results reveals samples with SnO2 shows more thermal stalibility due to Sn4+ interaction with amide and imide groups of PANI. SEM images of both nanocomposites showed an irregular morphology with agglomerate of particles, attributed to the presence of SnO2 nanoparticles which were not dispersed homogeneously during the synthesis process.