Banca de DEFESA: EWERTON LOPES PIRES NETO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : EWERTON LOPES PIRES NETO
DATE: 29/04/2026
TIME: 14:30
LOCAL: Videoconferência
TITLE:

Investigation of Hydrophobically Modified Guar Gum as an Additive in Aqueous Drilling Fluids.

KEY WORDS:

Guar Gum; alkylation; rheology; Drilling Fluids

PAGES: 85
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Orgânica
SPECIALTY: Polímeros e Colóides
SUMMARY:

The growing demand for environmentally sustainable alternatives in the oil industry has driven the use of polysaccharides as additives in drilling fluids. In this context, guar gum (GG), a polysaccharide widely used as a thickening agent, was hydrophobically modified through an alkylation reaction via Williamson synthesis using 1-bromohexane as the alkylating agent. The aim was to evaluate the potential of these derivatives to improve the properties of polysaccharides in water-based drilling fluids. The proposed synthesis resulted in two alkyl derivatives of GG with degrees of substitution of 0.07 and 0.19, which were characterized by infrared spectroscopy and hydrogen nuclear magnetic resonance (¹H NMR), dynamic light scattering (DLS) and size exclusion chromatography (SEC). Spectroscopic analyses confirmed the insertion of alkyl chains into the chemical structure of GG. The alkylated derivatives showed an increase in the average particle diameter in aqueous medium and a reduction in average molar mass, suggesting the formation of polymeric aggregates under static conditions at certain concentrations. All polymers aqueous solutions investigated exhibited rheological behavior typical of pseudoplastic fluids. With increasing degree of alkylation, an improvement in the thermal stability of guar gum derivatives was observed. Using a water-based drilling fluid considered as a standard, the performance of guar gum and its alkylated derivatives were evaluated as substitutes for xanthan gum. The results indicated that the chemical modification of guar gum through the proposed alkylation reactions provided improved drilling fluid properties, such as reduced filtrate volume and increased viscosities in the presence of salt and at high temperatures.

COMMITTEE MEMBERS:
Externo à Instituição - CESAR LIBERATO PETZHOLD - UFRGS
Interno - 1803692 - FABRICIO GAVA MENEZES
Interno - 1859346 - MIGUEL ANGELO FONSECA DE SOUZA
Presidente - 1149440 - ROSANGELA DE CARVALHO BALABAN