Banca de QUALIFICAÇÃO: MARAISA CRISTIANE DE OLIVEIRA LEITE

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : MARAISA CRISTIANE DE OLIVEIRA LEITE
DATE: 20/01/2020
TIME: 10:00
LOCAL: Sala de aula do PPGCEM
TITLE:

Accelerated aging effects on polymeric coatings reinforced with cellulose nanocrystals

KEY WORDS:

polymeric coating, cellulose nanocrystals, accelerated aging, corrosion.

PAGES: 72
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Polímeros, Aplicações
SUMMARY:

Organic coating is a type of film that forms a protective barrier between the environment and the substrate. However, defects in the coating layer provide ways in which corrosive species can reach the metal surface. Environmental factors such as humidity, temperature, UV radiation and erosion by salt ions can alter coatings and lead to decomposition. The insertion of nanoparticles can act through the barrier effect due mainly to its high degree of crystallinity and high surface area, providing an increase in the diffusion pathways of the aggressive ions to the metallic substrate. The increasingly frequent use of these polymeric coatings in various industrial applications raises concern about the influence of service conditions on the durability of the material. Thus, the objective of this work is to study the effects of accelerated aging and its efficiency in corrosion protection of organic epoxy coatings reinforced with cellulose nanocrystals. The characterization results of cellulose nanocrystals showed that they have high crystallinity and needle shape, as well as good thermal stability at high temperatures. The results of the dynamic mechanical analysis (DMA) showed that the insertion of nanocrystals caused an increase in storage modulus and Tg, and a decrease in tan delta due to good epoxy / nanocrystals interaction. FTIR spectra reveal that the addition of nanocrystals leads to the formation of hydrogen bonds between the reinforcement and the epoxy matrix, suggesting that a strong interphase region is formed. The insertion of nanocrystals in the epoxy matrix promoted a drop in permeability. This result was also confirmed in the electrochemical impedance spectroscopy (EIS).

BANKING MEMBERS:
Presidente - 2042234 - ANA PAULA CYSNE BARBOSA
Interno - 1300987 - CARLOS ALBERTO PASKOCIMAS
Externo ao Programa - 1064594 - EVANS PAIVA DA COSTA FERREIRA