Banca de DEFESA: THEÓGENES SILVA DE OLIVEIRA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : THEÓGENES SILVA DE OLIVEIRA
DATE: 22/02/2024
TIME: 10:00
LOCAL: Remoto
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:

A self-healing additive for cement pastes consisting of epoxy resin and catalyst (methyl ethyl ketone peroxide) encapsulated separately in silica microspheres was developed. Once dispersed in the cementitious matrix, the microspheres with encapsulated material break under the action of cracks or damage, putting the epoxy resin and the catalyst in contact so that the product of the polymerization reaction seals or retards the growth of the defect. The encapsulation process was based on a variation of the Stöber Method, widely used in the literature, for obtaining silica micro/nano spheres with encapsulated material. It was characterized by X-Ray Diffraction, Infrared Spectroscopy, Thermogravimetric Analysis, Scanning Electron Microscopy with EDS and BET Surface Area Analysis. The XRD result showed an amorphous disposition of the materials (encapsulated resin and catalyst), the FTIR result showed peaks related to resin and relative to methyl ethyl ketone peroxide for the encapsulated resin and encapsulated catalyst, respectively. The thermogravimetric analysis showed mass decay in the expected temperature regions for the decomposition of the materials involved and that the synthesized material is stable up to temperatures above 300°C. SEM-EDS showed that the method used was efficient in synthesizing silicon microcapsules and that these capsules are breakable under the incidence of mechanical stress. It also showed that the average size of the synthesized particles is in the range between 50 - 250 m. XRD analyzes showed the absence of crystallinity in the material obtained. The results obtained show 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 - ALCIVAN ALMEIDA EVANGELISTA NETO - IFRN
Externa à Instituição - KEILA REGINA SANTANA - UFERSA
Externo à Instituição - RAFAEL DA SILVA FERNANDES