Balaban, Rosangela de CarvalhoLima, Bruna Luiza Batista de2023-03-242023-03-242023-01-10LIMA, Bruna Luiza Batista de. Carboximetilcelulose hidrofobicamente modificada e sua aplicabilidade em fluidos de perfuração. Orientador: Rosângela de Carvalho Balaban. 2023. 110f. Tese (Doutorado em Química) - Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte, Natal, 2023.https://repositorio.ufrn.br/handle/123456789/51945Polymers extracted from renewable sources, such as polysaccharides, have attracted increasing interest of academia and industry, in order to obtain products applicable in different formulations as controlled release of drugs, thickeners in food and cosmetics, or even as additives in drilling fluids. In the petroleum industry, in particular, the development of new drilling fluids with characteristics similar to those of conventional synthetic drilling fluids, but that attend to environmental requirements, has been attracting the attention of researchers. In this sense, this work has as objective to obtain and characterize hydrophobically modified carboxymethylcellulose (CMC) and to evaluate its potential for application in aqueous and nonaqueous drilling fluids (olefin-based), as rheological modifiers. The products were obtained from the reaction between the carboxylic acid groups of CMC and the amino group from dodecylamine, via carbodiimide coupling. The materials were characterized by spectroscopy in infrared region (FTIR), hydrogen nuclear magnetic resonance (¹H NMR), conductimetric titration, solubility tests, zeta potential, dynamic light scattering (DLS), rheological measurements and confocal microscopy. The FTIR and ¹H NMR spectra of the derivatives showed an amide characteristic sign of amide group, proving that the reaction occurred. Through the solubility tests, it was observed that the CMC derivatives, unlike the precursor, showed turbidity in water, due to the hydrophobic groups inserted onto the CMC chains, which associate in polar medium. This behavior resulted in higher hydrodynamic diameter values for the derivatives in water, as observed by DLS. The rheological measurements in water also corroborated with the DLS data, as the viscosity of the derivatives was higher than that of CMC. The addition of salt to the aqueous medium resulted in even higher viscosities for the products. Confocal microscopy showed that the emulsion made with CMC derivative was more stable when compared to an emulsion made with a commercial product (BDF-990). Tests on aqueous and non-aqueous drilling fluids under high temperature and high-pressure conditions were performed evaluating viscosity measurements and filtration properties. In tests with aqueous drilling fluids, the derivative showed a viscosity close to CMC and a smaller filtrate volume, under conditions of low temperature and low pressure, as well as under conditions of high temperature and high pressure. For the tests with non-aqueous drilling fluids, the polysaccharide derivative showed higher viscosity values and lower filtrate volume values with comparison a commercial product used in oil industry (BDF-990). Therefore, CMC hydrophobic presented themselves as good alternatives for use in aqueous and non-aqueous drilling fluids, both for their improved performance and for being products from a renewable source.Acesso AbertoQuímicaCarboximetilceluloseDodecilaminaAmidaFluido de perfuração aquosoFluido de perfuração não-aquosodoctoralThesisCNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA