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Master's Dissertation
DOI
Document
Author
Full name
Gabriela Silva Ferreira Carvas
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2019
Supervisor
Committee
Aoki, Idalina Vieira (President)
Aquino, Isabella Pacifico
Cotting, Fernando
Title in Portuguese
Efeito autorreparador em primer carregado com inibidor de corrosão encapsulado em haloisita.
Keywords in Portuguese
Corrosão
Dodecilamina
EIS
Haloisita
Nanocontainer
Revestimentos
Abstract in Portuguese
O objetivo deste trabalho é avaliar o efeito autorreparador de um primer alquídico base solvente (SB) e um primer acrílico base água (WB) aditivados com nanocontainers de haloisita carregados com inibidor de corrosão dodecilamina (DDA) aplicados em aço carbono. O efeito inibidor da dodecilamina foi avaliado através de ensaios eletroquímicos de espectroscopia de impedância eletroquímica (EIS) em diferentes condições, sendo verificada que a sua eficiência aumenta em meio ácido. Com o intuito de aumentar o lúmen da haloisita, gerando mais capacidade de carregamento de inibidor, a haloisita foi tratada com ácido sulfúrico 2 mol/L por 6 h a 55 °C. A haloisita tratada foi caracterizada através de análises termogravimétricas (TGA) e microscopia eletrônica de varredura (MEV). Em seguida, a dodecilamina foi carregada em haloisita tratada, através da técnica de pulso de vácuo. A cinética de liberação do inibidor de dentro da haloisita foi estudada através da técnica de EIS, onde foi constatada que a sua atuação é dependente do pH, com maior velocidade de liberação em pH 2. Os nanocontainers foram adicionados em um primer alquídico base solvente e um primer acrílico base água para a avaliação da resistência à corrosão dos sistemas através de espectroscopia de impedância eletroquímica (EIS), técnica de varredura com eletrodo vibratório (SVET) e ensaios acelerados de corrosão em câmara de névoa salina (SSC). A aderência dos dois sistemas foi avaliada através do ensaio de aderência por tração (pull-off). Para os dois sistemas avaliados foi possível verificar o efeito autorreparador, porém ele não foi tão longo, provavelmente devido à baixa eficiência no carregamento da dodecilamina na haloisita. A análise de custo da haloisita carregada com dodecilamina mostrou a necessidade de otimização dos processos de carregamento a fim de viabilizar o projeto na indústria de tintas.
Title in English
Self-healing effect of primer loaded with corrosion inhibitor encapsulated in halloysite.
Keywords in English
Corrosion
Dodecylamine
EIS
Halloysite
Nanocontainer
Self-healing coating
Abstract in English
The aim of this work is to evaluate the self-healing effect of a solvent based (SB) alkyd primer and a water based (WB) acrylic primer loaded with dodecylamine (DDA) corrosion inhibitor encapsulated in halloysite nanocontainers on carbon steel. The inhibitor effect of dodecylamine was evaluated by electrochemical impedance spectroscopy (EIS) under different conditions, and it was verified that its efficiency increases in acid medium. To enlarge halloysite lumen and increase its loading capacity, halloysite was treated with 2 mol/L sulfuric acid for 6 h at 55 °C. Halloysite before and after treatment was characterized by thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). Thereafter, the dodecylamine was loaded into treated halloysite by the vacuum pulse technique. The release kinetics of the inhibitor from within halloysite nanotubes were studied through the EIS technique where it was found that the action of halloysite is pH-dependent, with a higher release kinetics at pH 2. The nanocontainers were loaded in a solvent based alkyd primer and a water based acrylic primer for the evaluation of the corrosion resistance of the systems through electrochemical impedance spectroscopy (EIS), scanning vibration electrode technique (SVET) and accelerated corrosion tests in a salt spray chamber (SSC). The adhesion of the two systems was evaluated through the pull-off adhesion test. For the two systems evaluated, it was possible to verify the self-healing effect, but this effect was not long, probably due to the low loading efficiency of dodecylamine in halloysite nanotubes. The cost analysis of halloysite loaded with dodecylamine showed that the loading process needs an optimization in order to make this project feasible in the coating industry.
 
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Publishing Date
2019-09-13
 
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