Study On The Preparation Of Polypyrrole Nanocomposites With Optoelectronic And Adsorption Properties

As a typical intrinsic conducting polymers, polypyrrole (PPy) has excellent conductive performance, anti-oxidation and high thermal stability. So, PPy has contracted more and more attention. PPy is widely applied in the fields of secondary battery, biological sensors, nonlinear optical devices, electrically induced color display and functional molecular film. Polypyrrole/semiconductor nanoparticles composites contain both the original characteristics of polymer materials and the characteristics of nanoparticles, so, they should be studied further. In this thesis, PPy/ CdS composites were synthesized and their photoelectric and adsorption properties were studied.(1) PPy/CdS nanocomposites have been synthesized by means of interfacial polymerization-in-situ method. The products were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM-EDAX), ultraviolet absorption (UV-Vis) and thermogravimetric Analysis (TGA). The PPy/CdS film as prepared has a smooth surface. Effect of the charge ratio of CdS on the scales of CdS nanorods was studied. The Z-scan technique were introduced to study third order nonlinear optical (NLO) properties of PPy/CdS. The PPy/CdS has obvious saturated absorption and nonlinear refraction. The nonlinear refractive coefficient of PPy/CdS (10:1) thin film is 2.4 times of PPy film. Similarly, the third-order nonlinear polarizability of PPy/CdS (10:1) is 2.1 times of PPy. The composite material shows a potential application in the field of optical limiting materials and other photoelectric field.(2) The photodegradation of methylene blue was investigated by using the PPy/CdS nanocomposites as catalyst. Compared to CdS, PPy/CdS nanocomposites show a higher photodegradation efficiency for methylene blue. Effects of the initial concentration, reaction time, catalyst dosage, pH value and reaction temperatureon the the degradation of methylene blue were studied. The results indicated that the photocatalytic degradation rate of methylene blue reached 97.51% as the initial concentration of methylene blue was 5 mg/L, the PPy/CdS usage was 15 g/L, the pH of methylene blue solution was about 7, the illumination time was 15min and the light intensity was 200W.(3) The removal efficiency of Cr (?) was investigated by using the PPy and PPy composites as absorbents. Effects of pH, temperature, adsorption time, concentration of Cr (?), dosage of PPy on the Cr (?) removal rate were discussed. Polypyrrole/glass filter membrance showed an excellent performance for removal of Cr (?) from water. The removal efficiency of Cr(?) was up to 82.5% as the Cr(?) initial concentration was 50 mg/L, the pH of Cr(?) solution was about 3, the composites dosage was 6 g/L and the absorption time was 15 min.