A Comparative Study on Graphene Oxide and Carbon Nanotube Reinforcement of PMMA-Siloxane-Silica Anticorrosive Coatings

Autor(es)

Harb, Samarah V. ^[1] ; Pulcinelli, Sandra H. ^[1] ; Santilli, Celso V. ^[1] ; Knowles, Kevin M. ^[2] ; Hammer, Peter ^[1]

Afiliação do(s) autor(es)

^[1] UNESP Univ Estadual Paulista, Inst Quim, BR-14800060 Araraquara, SP - Brazil

^[2] Univ Cambridge, Dept Mat Sci & Met, 27 Charles Babbage Rd, Cambridge CB3 0FS - England

• Tipo de documento: Artigo Científico
• Fonte: ACS APPLIED MATERIALS & INTERFACES; v. 8, n. 25, p. 16339-16350, JUN 29 2016.
• Citações Web of Science: 14

Resumo

Carbon nanotubes (CNTs) and graphene oxide (GO) have been used to reinforce PMMA-siloxane-silica nanocomposites considered to be promising candidates for environmentally compliant anticorrosive coatings. The organic inorganic hybrids were prepared by benzoyl peroxide (BPO)-induced polymerization of methyl methacrylate (MMA) covalently bonded through 3-(trimethoxysilyl)propyl methacrylate (MPTS) to silica domains formed by hydrolytic condensation of tetraethoxysilane (TEOS). Single-walled carbon nanotubes and graphene oxide nanosheets were dispersed by surfactant addition and in a water/ethanol solution, respectively. These were added to PMMA-siloxane-silica hybrids at a carbon (CNT or GO) to silicon (TEOS and MPTS) molar ratio of 0.05% in two different matrices, both prepared at BPO/MMA molar ratios of 0.01 and 0.05. Atomic force microscopy and scanning electron microscopy showed very smooth, homogeneous, and defect-free surfaces of approximately 3-7 mu m thick coatings deposited onto A1020 carbon steel by dip coating. Mechanical testing and thermogravimetric analysis confirmed that both additives CNT and GO improved the scratch resistance, adhesion, wear resistance, and thermal stability of PMMA-siloxane-silica coatings. Results of electrochemical impedance spectroscopy in 3.5% NaCl solution, discussed in terms of equivalent circuits, showed that the reinforced hybrid coatings act as a very efficient anticorrosive barrier with an impedance modulus up to 1 G Omega cm(2), approximately 5 orders of magnitude higher than that of bare carbon steel. In the case of GO addition, the high corrosion resistance was maintained for more than 6 months in saline medium. These results suggest that both carbon nanostructures can be used as structural reinforcement agents, improving the thermal and mechanical resistance of high performance anticorrosive PMMA-siloxane-silica coatings and thus extending their application range to abrasive environments. (AU)

• Processo FAPESP: 14/12182-9 - Análise mecânica por nanoindentação, microscratch e testes de desgaste de revestimentos anticorrosivos híbridos siloxano-PMMA reforçados por nanotubos de carbono e grafeno
• Beneficiário: Samarah Vargas Harb
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Mestrado
• Processo FAPESP: 13/04314-0 - Desenvolvimento de revestimentos siloxano-PMMA reforçados por nanotubos de carbono e grafeno para aplicações anticorrosivas
• Beneficiário: Samarah Vargas Harb
• Modalidade de apoio: Bolsas no Brasil - Mestrado