Banca de QUALIFICAÇÃO: THEÓGENES SILVA DE OLIVEIRA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : THEÓGENES SILVA DE OLIVEIRA
DATE: 29/08/2023
TIME: 08:30
LOCAL: Auditório do Laboratório de Cimentos da UFRN
TITLE:

Silica microcapsules for self-repair of oilwell cement pastes

KEY WORDS:

Self-repair, microencapsulation, well cementing, Stöber Method.

PAGES: 100
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Materiais Conjugados Não-Metálicos
SUMMARY:

The exploration and production of oil and gas demand important precautions concerning  the environment, and new technologies play a fundamental role in meeting this goal. In particular, economically viable cement pastes that offer high resistance to the propagation of cracks and damage are an important environmental safety factor. Thus, the objective of this work is to develop a self-healing additive for cement pastes consisting of epoxy resin and catalyst (methyl ethyl ketone peroxide) encapsulated separately in silica microspheres. Once dispersed in the cementitious matrix, the microspheres with encapsulated material break under the action of cracks or damage, bringing the epoxy resin and the catalyst into contact so that the product of the polymerization reaction seals or retards the growth of the crack. The encapsulation process was based on a variation of the Stöber Method, widely reported in the literature, for obtaining silica micro/nano spheres with encapsulated material. The spheres were characterized by X-Ray Diffraction, Infrared Spectroscopy, Thermogravimetric Analysis, Scanning Electron Microscopy with EDS and BET Analysis. The XRD results revealed the amorphous nature of the materials (encapsulated resin and catalyst). The FTIR result showed peaks related to resin and silicon, and methylethylketone peroxide and silicon for the encapsulated resin and encapsulated catalyst, respectively. The thermogravimetric analysis showed mass loss in the expected temperature regions for the decomposition of the materials involved. The SEM-EDS showed that the average size of the synthesized particles is in the range between 40-50 nm. The BET analysis showed a pore volume of 1.5 cm³/g for the studied samples, which is consistent with the particle size range. The results obtained showed that the synthesis process was successful for both the encapsulated resin and the encapsulated catalyst.

COMMITTEE MEMBERS:
Presidente - 1298936 - ANTONIO EDUARDO MARTINELLI
Interno - 1804366 - JÚLIO CÉZAR DE OLIVEIRA FREITAS
Externo à Instituição - RAFAEL DA SILVA FERNANDES - UFRN