Banca de QUALIFICAÇÃO: JOÃO FREIRE DE MEDEIROS NETO

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : JOÃO FREIRE DE MEDEIROS NETO
DATA : 12/07/2019
HORA: 09:00
LOCAL: Sala 414 do CTEC - UFRN
TÍTULO:

EFFICIENCY OF PLASMA IN DIELECTRIC BARRIER DISCHARGE IN MATERIAL MODIFICATION: EFFECT ON THE PHYSICAL-QUANTITY ALTERATIONS OF HIGH DENSITY POLYETHENE AND TITANIUM

PALAVRAS-CHAVES:

Plasma DBD, HDPE, Titanium, Langmuir, Wettability

PÁGINAS: 60
GRANDE ÁREA: Engenharias
ÁREA: Engenharia Mecânica
RESUMO:

The work utilized the dielectric barrier discharge (DBD) technique for surface modification of high density polyethylene (HDPE) and Titanium. The treatments were made in argon or oxygen for 10 minutes at a frequency of 820 Hz, voltage of 20 kV, 2 mm distance between electrodes and atmospheric pressure for HDPE and for titanium, the gas was atmospheric air, 1, 5 mm distance between the electrodes and the treatment lasted 30 minutes, the other parameters were the same. Plasma efficiency was measured using a Langmuir triple probe to verify that it had sufficient energy to promote possible chemical changes on the surface of the material. The physicochemical alterations were diagnosed through a technique of surface characterization as contact angle, X-ray excitation (XPS) spectroscopy. The Fourier Fourrier Fourier Fourrier (FTIR-ATR) attenuated total reflection spectroscopy was performed only for the HDPE for comparison purposes with the modifications obtained by the XPS. The plasma electronic temperature showed that it has sufficient energy for the breaking or formation of chemical bonds on the HDPE surface, directly impacting the wettability. For the HDPE, the wettability test was done before and after the treatment through sessile drop, using distilled water, glycerin and dimethylformamide, to trace the surface tensions profile by the fowkes method, analyzing the variation of the contact angle. The FTIR-ATR and XPS showed the groups and bonds that were altered or generated superficially when compared to the untreated sample. The wettability test for Titanium was done in the same way, but water, formamide and glycerine were used, and the method of van Oss, Chaudhury and Good was used for the profile of interfacial tensions. The morphological characterization of titanium was investigated by MEV and AFM, showing that there was increase of roughness at the nanometric scale.

MEMBROS DA BANCA:
Presidente - 2550377 - THERCIO HENRIQUE DE CARVALHO COSTA
Externo à Instituição - EDSON JOSÉ DA COSTA SANTOS - IFRN
Externo à Instituição - IVAN ALVES DE SOUZA
Externa à Instituição - THARSIA CRISTIANY DE CARVALHO COSTA - IFBA