Effect of curing temperature and architectural (monolayer and bilayer) of hybrid films modified with polyethylene glycol for the corrosion protection on tinplate

Abstract

Hybrid films obtained by a sol-gel process are based on two important reactions: hydrolysis and condensation. The condensation reaction is influenced by the curing temperature, since it induces the development of the intrinsic properties of the gel. The aim of this work is to coat tinplate, a substrate widely used in the packaging industry, with monolayered and bilayered hybrid films modified with polyethylene glycol and obtained through dip-coating. The results showed that the bilayered hybrid film obtained at 60°C had a higher layer thickness, and the best performance in the electrochemical assays, as well as the most hydrophobic character, in relation to the other samples. For the monolayered systems, the 90°C-cured system showed a lower layer thickness; however, this system showed a more compact, uniform and less porous layer, and presented better electrochemical impedance results, in comparison with the 60°C-cured samples.

Electrochemical and Mechanical Behavior of Uv Curing Paint on Hybrid Films Modified With Polyethyleneglycol Plasticizer Applied on Tinplate

“…As shown in another study by this group of researchers [6], good electrochemical performance of the samples with coating, wich are displayed in the diagrams of Nyquist and Bode, proves the fact that the small increase in branch ethylene oxide (20 g.L -1 ) is sufficient to reduce the condensation reaction rate of triorganosilanols groups. The condensation of the tetrafunctional alkoxide was also delayed in the presence of the monomer (PEG) due to the increased steric hindrance in the transition state; therefore, a more flexible film was obtained with improved substrate adhesion promoting an improvement in anticorrosive properties of the coating.…”

“…This deficiency is mainly related to the poor adherence of the film and to the shrinkage of the film after curing [6]. Thus, it is necessary to coat the surface in a conventional manner through a thermal treatment system using solvents with high content of volatile organic compounds (VOCs), which pollute the atmospheric air due to their photochemical reactions with nitrogen oxides (NOx) that exist in the atmosphere [8].…”

“…The UV curing process is an environmentally friendly process is what stands out as the main advantage of this technology [5]. However, there are disadvantages to the use of the radiation-curing ultravileta process for example, th acrylic monomers normally have high levels of irritability, UV radiation can form ozone, and UV curing systems can cause poor healing in highly pigmented systems [6]. In addition, one of the main problems system is the fact that most of the cured coatings researched thus far have presented deficient mechanical [7].…”

Corrosion Mechanism Suggested Based on Electrochemical Analysis and SVET for Uncoated Tinplate and Post Coated With a Hybrid Film

“…For this reason, the hybrid films have been proposed, since they are associated as part of a same matrix, with organic and inorganic components and combine the most important properties of each constituent 17,18 . Because they are compatible with overlying organic top-coats, eco-friendly sol-gel derived coatings can also present good adhesion to metallic surfaces via chemical bonding 19 . Furthermore, due the numerous application parameters and curing of hybrid films, an enhanced adhesion might be expected, as metallosiloxane bonds are formed during the condensation reaction.…”

“…Furthermore, due the numerous application parameters and curing of hybrid films, an enhanced adhesion might be expected, as metallosiloxane bonds are formed during the condensation reaction. Formation of siloxane chains through the condensation of silanol groups in excess could also yield a dense network layer acting as an effective barrier against aggressive species [18][19][20] .…”