No abstract

obtido foi caracterizado por espectroscopia no infravermelho por transformada de Fourier (FTIR), varredura diferencial de calorimetria (DSC) e análise termogravimétrica (TGA). Propriedades óticas do (PSt-co-PMSt)-g-PANI nos estados não-dopado e dopado foram obtidas usando espectroscopia no ultravioleta-visível (UV-Vis), e condutividade elétrica a temperatura ambiente foi medida usando amostras nas quais os materiais condutores foram ensanduichados entre dois eletrodos de Ni. Além disso, eletroatividade do terpolímero sintetizado foi verificada sob condições voltamétricas sobre a superfície do eletrodo de trabalho de carbono vítreo (GCE). A solubilidade do terpolímero (PSt-co-PMSt)-g-PANI foi examinada em solventes orgânicos comuns, tais como, tetrahidrofurano (THF), clorofórmio e xileno.This study aims to explore an effective route for the preparation of conductive N-substituted polyaniline (PANI) by the incorporation of brominated poly(styrene-co-p-methylstyrene) onto the emeraldine form of polyaniline. For this purpose, at first, poly(styrene-co-p-methylstyrene) was synthesized via nitroxide-mediated polymerization (NMP), and then, N-bromosuccinimide was used as brominating agent to obtain a copolymer with bromine. Thereafter, deprotonated polyaniline was reacted with brominated poly(styrene-co-p-methylstyrene) to prepare the poly(styrene-co-p-methylstyrene)-graft-polyaniline [(PSt-co-PMSt)-g-PANI] terpolymer through N-grafting reaction. The terpolymer was characterized by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Optical properties of (PSt-co-PMSt)-g-PANI in the undoped and doped states were obtained by ultraviolet-visible spectroscopy (UV-Vis), and electrical conductivity at room temperature was measured using samples in which the conductive materials was sandwiched between two Ni electrodes. Moreover, electroactivity of the synthesized terpolymer was verified under cyclic voltammetric conditions on the surface of the working glassy carbon electrode (GCE). The solubility of (PSt-co-PMSt)-g-PANI terpolymer was examined in common organic solvents, such as, tetrahydrofuran (THF), chloroform and xylene.

In this report, TiO(2) -SiO(2) composite nanoparticles were prepared by the thermal hydrolysis method using titanium tetrachloride and tetraethylorthosilicate as TiO(2) and SiO(2) precursors, respectively. The prepared nanoparticles were characterized by X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), nitrogen adsorption/desorption and UV-Vis diffuse reflectance spectroscopy (DRS). The results indicated that, in comparison with pure TiO(2), TiO(2)-SiO(2) composite nanoparticles had a higher thermal stability, which prevents phase transformation from anatase to rutile. In addition, the TiO(2)-SiO(2) nanoparticles had a higher specific surface area, larger pore volume, greater band gap energy and smaller crystallite size. Thus, the surface area of TiO(2)-40% SiO(2) composite nanoparticles was about 17 times higher than that of pure TiO(2) nanoparticles. The photocatalytic activity of TiO(2)-SiO(2) composite nanoparticles in the photodegradation of C.I. Basic Violet 2 was investigated. The photodegradation rate of Basic Violet 2 using TiO(2)-40% SiO(2) nanoparticles calcined at 600°C was much faster than that using pure TiO(2) and Degussa P25 TiO(2) by 10.9 and 4.3 times, respectively. The higher photoactivity of the TiO(2)-SiO(2) composite nanoparticles was attributed to their higher surface area, larger pore volume, greater band-gap energy and smaller crystallite size compared with pure TiO(2).

No abstract

No abstract

No abstract

No abstract

No abstract