Rede polimérica a base de polidimetilsiloxano funcionalizado com grupo amino contendo dióxido de titânio para aplicação na degradação do corante azul de metileno

Abstract

In recent years, demographic growth has been observed, and to meet the needs of these people, there has been an intensification of industrial activities. Consequently, these factories generate more waste, disposing of it inadequately in aqueous effluents, causing serious environmental problems, as example the dyes. In this context, a polymeric network based on functionalized poly(dimethylsiloxane) (PDMS) containing titanium dioxide was synthesized to explore its degradation property against methylene blue dye. This network was prepared with the following precursors: poly(dimethylsiloxane) (PDMS), 3-aminopropyltrimethoxysilane (APTMS), 3- chloropropyltrimethoxysilane (CPTMS), and titanium dioxide. The prepared materials were named DPAC – 0.125, DPAC – 0.250, DPAC – 0.500, DPCC – 0.500, and PAC according to the mass/mass ratio of PDMS to TiO2. The synthesized materials were characterized by Fouriertransform infrared spectroscopy (FTIR), X-ray diffraction (DRX), thermogravimetric analysis (TA), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). With infrared spectroscopy it was possible to identify the characteristic bands of a functionalized polymeric network containing titanium dioxide. Through thermogravimetric analysis, it was possible to determine the thermal stability of the materials, with the DPAC – 0.500 and DPCC – 0.500 networks being the most stable, with a maximum degradation peak at 660°C and generating higher residual content, 49.9% and 47.7%, respectively. X-ray diffraction indicated the stability of the anatase phase of titanium dioxide after network formation, with its main characteristic peak at the 2θ position at the angle of 25.3º. Scanning electron microscopy and energy-dispersive X-ray spectroscopy allowed the evaluation of the surface morphology of the materials and the mapping of the distribution of the atoms present in the materials. Finally, degradation reactions were performed for the materials, evaluating the degradation kinetics and the discoloration rate, concluding that the materials with the highest titanium dioxide content, DPAC – 0.500 and DPCC – 0.500, showed the highest discoloration rate and the fastest kinetics.