ǂthe ǂeffect of copolymerization time
Peter Rodič (Author), Romana Cerc Korošec (Author), Barbara Kapun (Author), Alenka Mertelj (Author), Ingrid Milošev (Author)

Abstract

Pre-hydrolysed/condensed tetraethyl orthosilicate (TEOS) was added to a solution of methyl methacrylate (MMA) and 3-methacryloxypropyltrimethoxysilane (MAPTMS), and then copolymerised for various times to study the influence of the latter on the structure of hybrid sol-gel coatings as corrosion protection of aluminium alloy 7075-T6. The reactions taking place during preparation were characterised using real-time Fourier transform infrared spectroscopy, dynamic light scattering and gel permeation chromatography. The solution characteristics were evaluated, using viscosimetry, followed by measurements of thermal stability determined by thermogravimetric analysis. The optimal temperature for the condensation reaction was determined with the help of high-pressure differential scanning calorimetry. Once deposited on 7075-T6 substrates, the coatings were evaluated using a field emission scanning electron microscope coupled to an energy dispersive spectrometer to determine surface morphology, topography, composition and coating thickness. Corrosion properties were tested in dilute Harrison’s solution (3.5 g/L (NH$_4$)$_2$SO$_4$ and 0.5 g/L NaCl) using electrochemical impedance spectroscopy. The copolymerization of MMA and MAPTMS over 4 h was optimal for obtaining 1.4 µm thick coating with superior barrier protection against corrosion attack (|Z$_{10}$ $_{mHz}$| ~ 1 GΩ cm$^2$) during three months of exposure to the corrosive medium.

Keywords

AA7075-T6;hybrid sol-gel;copolymerization;corrosion;dilute Harrison’s solution;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UL FKKT - Faculty of Chemistry and Chemical Technology
UDC: 620.1/.2
COBISS: 33305639 Link will open in a new window
ISSN: 2073-4360
Views: 168
Downloads: 60
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Other data

Type (COBISS): Article
Pages: str. 948-1-948-26
Volume: ǂVol. ǂ12
Issue: ǂno. ǂ4
Chronology: 2020
DOI: 10.3390/polym12040948
ID: 14092617