Engenharia Química
URI permanente desta comunidadehttps://repositorio.fei.edu.br/handle/FEI/25
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2 resultados
Resultados da Pesquisa
- Alkyd resin synthesis by enzymatic alcoholysis(2019) de Carvalho R.K.C.; Ortega F.S.; Morandim-Giannetti A.A.© 2019, Iran Polymer and Petrochemical Institute.The synthesis of an alkyd resin through an enzymatic alcoholysis provided by Novozym 435 was analyzed in this study. The alcoholyses were performed in different enzyme concentrations (2.63, 4.00, 6.00, 8.00, and 9.36%, based on oil’s mass), oil/glycerin ratios (1.68, 2.50, 3.50, 4.50, and 5.18 oil mol/glycerin mol), at temperatures (33.18, 40.00, 50.00, 60.00, and 66.82 °C) to determine the best reaction conditions for obtaining the highest percentage of monoacylglycerides and diacylglycerides [glycerin/vegetal oil ratio of 1:3.5 (mol/mol), at temperature of 56.73 °C, and 9.36% enzyme concentration based on oil’s mass (w/w)]. It was verified that 2 h was the ideal reaction time. Under the best alcoholysis condition, the alkyd resin was produced using phthalic anhydride and the product presented similar characteristics as the current resin produced by a chemical catalyst in the industrial process (final viscosity = Y2, solid content = 44.00%, and IA ≤ 12). 1H NMR and FTIR analyses confirmed the formation of an alkyd resin as they showed the presence of characteristic signals of the final product. The re-usability of the enzyme was investigated, and significant results were observed in the reaction after five cycles (by activity reduction of 6%) showing the viability of applying enzymatic steps in industrial procedures to produce resins in the future, once the application of enzymes also reduced the level of toxicity in the processes.
- Attainment of cellulose acetate from coir fiber submitted to pretreatment with IL n-butylammonium acetate(2019) de Andrade Neto J.C.; de Almeida A.C.; dos Santos Machado C.; Coelho D.O.; Mourad N.; Teixeira N.S.; Pereira G.J.; Morandim-Giannetti A.A.© 2019, Iran Polymer and Petrochemical Institute.Cellulose acetate was obtained from the coir fiber submitted to the treatment with the IL. The coir fiber was initially subjected to treatment with the n-butylammonium acetate IL (CFIL) and subsequent bleaching (CFILB). By analyzing the CFILB, it was possible to observe a delignification of 6.10% in relation to the natural material and an 8.1% increase in the concentration of cellulose. The results from SEM, XRD, and FTIR-ART confirm the modifications in the fiber. After characterizing the treated coir fiber and obtaining the cellulose acetate, analyses by NMR confirmed its regeneration with a degree of substitution at 2.92. FTIR analyses corroborate with the obtained data, verifying the presence of the main adsorption bands. The XRD analysis of cellulose acetate shows peaks at 8.5° regarding the randomness after the acetylation of cellulose, as well as peaks between 18° and 22.5° regarding the packing of carbon atoms due to the Van der Waals forces, which confirm the production of cellulose acetate. The thermal analysis shows that decomposition events occurred in two stages, indicating the thermal decomposition of the remaining cellulose, which did not undergo acetylation, and attribution to its thermal degradation.