Preparação e caracterização de sistemas híbridos poli (etileno-co-acetato de vinila)/bentonita/níobio com potencial aplicação para fotodegradação do corante rodamina b

• Autor(a) principal: Barra, Heliton
• Data de Publicação: 2024
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UTFPR (da Universidade Tecnológica Federal do Paraná (RIUT))
• Texto Completo: http://repositorio.utfpr.edu.br/jspui/handle/1/34428
• topic: Óxido de nióbio; Ressonância magnética nuclear; Bentonita; Argila - Análise; Espectroscopia de infravermelho; Misturas (Química); Niobium oxide; Nuclear magnetic resonance; Bentonite; Clay - Analysis; Infrared spectroscopy; Mixtures; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::QUIMICA ORGANICA; Química

The latest technologies demand materials with properties that are not normally found in conventional materials, such as polymers, ceramics and metals. Hybrid structures made up of combinations of organic and inorganic components generally interact through a synergistic effect, giving rise to a single material with properties that differ from those of the original compounds. This alternative can be used in the development of compounds with diverse applications. In this context, interest in the use and production of materials based on inorganic fillers supported on polymers has become a trend, and poly(ethylene-co-vinyl acetate) (EVA) can be used as a building block for polymeric hybrid composites. In this context, the aim of this work was to prepare EVA/niobium pentoxide (Nb2O5) or EVA/bentonite-Nb2O5 clay hybrid systems for use in the photodegradation of rhodamine B dye. The EVA/inorganic filler compositions were prepared in an intensive laboratory mixer in percentages of 3, 5 and 7% (w/w). The precursor materials were analyzed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy coupled with electron dispersion spectroscopy (SEMEDS) and thermogravimetric analysis (TGA). According to the results obtained, it was possible to evaluate the structural and chemical profile of the compounds and compare them with the literature based on other studies already carried out.For niobium pentoxide, the results showed crystalline characteristics, differentiating it from niobic acid, an amorphous material.The bentonite clay showed a hydrophilic profile and good swelling capacity, making it compatible for supporting semiconductor elements.The hybrid materials were evaluated by FTIR, XRD, TGA and low-field nuclear magnetic resonance (NMR-BC), as well as visual aspects, processing parameters via injection, reology and photodegradation tests.The results showed that the incorporation of inorganic fillers altered the polymer’s properties, such crystallinity and rheological properties. With regard to photodegradation analysis, the results obtained using the EVA hybrid material with 7% modified clay with niobium suggest a decrease in the maximum absorption band (355 nm) responsible for staining the rhodamine B dye over the 240-minutes analysis period, reaching 95.45% decolorization. Therefore, given the results presented, the proposal to prepare a hybrid material for the purpose of photodegradation was achieved, with the composition EVA/bentonite clay-Nb2O5 (7%) being the one that stood out in terms of efficiency as a photocatalyst, to justify the success of the research and the relevance of the compounds as an alternative of interest for the study area.