Study On Synthesis And Characterization Of Polyaniline-Tin Dioxide Nanocomposite Materials

Sol-gel method was used to prepare SnO₂ nanoparticles. XRD and FT-IR results showed that the product is tetragonal rutile structure. TEM photographs showed that the diameter of nanoparticles were between 15-30 nm. Some parts are reunited by two or three junior nanocrystals. Hexagonal ZnO nanoparticles were prepared by direct precipitation method. Sol-gel method was used to prepare the SnO₂ nanoparticles doped with ZnO. XRD and TEM were used to inspect the influences of ZnO on the diameter and morphology of SnO₂. The results showed that it can be divided into four stages. When doping content was more than 50%, ZnO separated from the SnO₂ crystallites and formed two-phase structure.Chemical oxidative polymerization of aniline in the presence of hydrochloric acid was performed in the present work. After being dedoped by ammonium, eigenstate polyaniline was obtained. XRD, FT-IR, UV-Vis, SEM, TEM and TGA were used to characterize the compositon, structure, performance and the micro-morphology of polyaniline. The following results were obtained. The eigenstate polyaniline was typically amorphous while the crystallinity of doped polyaniline was much better than the former. Micro-morphology characterization showed that polyaniline was composed of irregularly shaped particulates with diameter between 0.5-1μm and rod shaped nanostructures which is 0.2μm width, 1μm long. The interaction between polyaniline molecular chains doped with hydrochloric acid are much stronger than that of between eigenstate polyaniline molecular chains, so the former agglomerated to form bigger Particulate in micron scale while the latter is comparatively loosly. According to experiment results, polyaniline's thermal stability is fairly well. Its decomposition temperature is 450℃.PANI-SnO₂ nanocomposite materials were synthesized by in-situ polymerization method. XRD, FT-IR, SEM, TEM and TGA were used to characterize the composition, structure, performance and micro-morphology of the materials. The results showed that the composite materials were "cake-chocolate" structure. There exists chemical interaction between the inorganic phase and polymer phase: Sn atom's 5d orbit on the surface of nanoparticles accepted the sole pair of electron from N atom on the polyaniline molecular chain to form the coordinate bond. Similarly there exists H-bonding between the O atom (on the SnO₂ nanoparticle) and H atom (on the molecular chain), hydroxyl (on the SnO₂ nanoparticle) and N atom (on the molecular chain). The interaction lead that the crystallinity of polyaniline doped with hydrochloric decreased and the absorption peak of the polyaniline shifted. Because the polymer base has fixation effect on the nanoparticles, SnO₂ nanoparticles dispersed better than the pure inorganic phase. However the introduction of inorganic phase had little effect on the UV-Vis absorption peak and thermal stability of polyaniline. On the base of the upper analysis, the thesis gave the models of interaction process and molecular.