Desenvolvimento de filme híbrido orgânico-inorgânico siloxano-PU pelo processo sol-gel
Carregando...
Data
2017-02-24
Autores
Braz, Álvaro Guimarães [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
Nesse trabalho desenvolveu-se um método de síntese baseado na rota sol-gel para preparar materiais híbridos orgânico-inorgânicos formados por poliuretano e siloxano. Na síntese do poliuretano foi utilizado o 4,4’-metileno bis(isocianato de fenila) (4,4’-MDI), um diisocianato que contem dois anéis aromáticos em sua estrutura e o glicerol, um poliol derivado da produção do biodiesel que contém três grupos hidroxilas em sua estrutura. Utilizou-se também o (3-Aminopropil) trietoxisilano (APTES), um organo silano que interliga o poliuretano e tetraetoxisilano (TEOS) promovendo a ligação covalente entre as fases orgânica e inorgânica do material. Avaliou-se o efeito da razão entre as fases orgânica e inorgânica a partir da variação da proporção de APTES + TEOS em relação aos demais reagentes. Para caracterizar a eficiência da rota de síntese na obtenção do material hibrido com cadeias reticuladas de poliuretano, utilizou-se a espectroscopia vibracional no infra-vermelho por transformada de Fourier (FTIR), ressonância magnética nuclear (RMN), difração de raios X (DRX) e o espalhamento de raios X a baixo ângulo (SAXS). Para avaliar as propriedades térmicas, macroestruturais e de barreira dos materiais realizou-se análises de termogravimetria (TG), microscopia óptica, molhabilidade, microscopia de forças atômicas (AFM) e espectroscopia de impedância eletroquímica (EIS). Com base nas técnicas de FTIR, RMN, DRX, SAXS, foi confirmada a formação das cadeias polimérica reticuladas de PU e a conjugação com a sílica. A partir da TG observou-se a boa estabilidade térmica do material frente à vaporização e a combustão. AFM em conjunto com o teste de molhabilidade, mostrou que a amostra SPU-1.00 com menor rugosidade é mais hidrofóbica. As análises de EIS demonstram que as amostras SPU-1.00 e 1.25 são eficientes como barreiras anticorrosivas, apresentando tempo de vida superior a 170 dias de imersão em solução salina. Estes resultados inéditos obtidos com híbridos a base de poliuretano sintetizados a partir do glicerol potencializam a valorização da biomassa na produção de biocombustíveis e derivados de maior valor agregado.
In this work a synthesis method based on the sol-gel route was developed to prepare hybrid organic-inorganic materials formed by polyurethane and siloxane. In the synthesis of the polyurethane, 4,4'-methylene bis (phenyl isocyanate) (4,4'-MDI) was used, a diisocyanate containing two aromatic rings in its structure and glycerol, a polyol derived from the production of biodiesel that Contains three hydroxyl groups in its structure. Was also used (3-Aminopropyl) triethoxysilane (APTES), an organosilane interleaving the polyurethane and tetraethoxysilane (TEOS) promoting covalent attachment between the organic and inorganic phases of the material. The effect of the ratio between the organic and inorganic phases was evaluated from the variation of the APTES + TEOS ratio in relation to the other reagents. To characterize the efficiency of the synthesis route in obtaining hybrid material with polyurethane crosslinked chains, was used, Fourier transform infra-red spectroscopy (FTIR), nuclear magnetic resonance (NMR), X-ray diffraction (XRD) and low angle X-ray scattering (SAXS). The thermogravimetry (TG), optical microscopy, wettability, atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS) analyzes were performed to evaluate the thermal, macrostructural and barrier properties of the materials. Based on the techniques of FTIR, NMR, XRD, SAXS, the formation of the crosslinked polymer chain of PU and silicon conjugation was confirmed. From TG the good thermal stability of the material was observed against vaporization and combustion. AFM in conjunction with the wettability test showed that the SPU-1.00 sample with less roughness is more hydrophobic. The EIS analyzes show that the SPU-1.00 and 1.25 samples are efficient as anti-corrosion barriers, with a life time greater than 170 days of immersion in saline solution. These unprecedented results obtained with hybrids based on polyurethane synthesized from glycerol enhance the valorization of biomass in the production of biofuels and derivatives with higher added value.
In this work a synthesis method based on the sol-gel route was developed to prepare hybrid organic-inorganic materials formed by polyurethane and siloxane. In the synthesis of the polyurethane, 4,4'-methylene bis (phenyl isocyanate) (4,4'-MDI) was used, a diisocyanate containing two aromatic rings in its structure and glycerol, a polyol derived from the production of biodiesel that Contains three hydroxyl groups in its structure. Was also used (3-Aminopropyl) triethoxysilane (APTES), an organosilane interleaving the polyurethane and tetraethoxysilane (TEOS) promoting covalent attachment between the organic and inorganic phases of the material. The effect of the ratio between the organic and inorganic phases was evaluated from the variation of the APTES + TEOS ratio in relation to the other reagents. To characterize the efficiency of the synthesis route in obtaining hybrid material with polyurethane crosslinked chains, was used, Fourier transform infra-red spectroscopy (FTIR), nuclear magnetic resonance (NMR), X-ray diffraction (XRD) and low angle X-ray scattering (SAXS). The thermogravimetry (TG), optical microscopy, wettability, atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS) analyzes were performed to evaluate the thermal, macrostructural and barrier properties of the materials. Based on the techniques of FTIR, NMR, XRD, SAXS, the formation of the crosslinked polymer chain of PU and silicon conjugation was confirmed. From TG the good thermal stability of the material was observed against vaporization and combustion. AFM in conjunction with the wettability test showed that the SPU-1.00 sample with less roughness is more hydrophobic. The EIS analyzes show that the SPU-1.00 and 1.25 samples are efficient as anti-corrosion barriers, with a life time greater than 170 days of immersion in saline solution. These unprecedented results obtained with hybrids based on polyurethane synthesized from glycerol enhance the valorization of biomass in the production of biofuels and derivatives with higher added value.
Descrição
Palavras-chave
Híbrido orgânico-inorgânico, Poliuretano, Glicerol, Caracterização estrutural, Corrosão, Organic-inorganic hybrid, Polyurethane, Glycerol, Structural characterization, Corrosion