Influence of radical photoinitiator content on UV curing process and UV-cured hybrid sol–gel filmsShow others and affiliations
2020 (English)In: JCT Research, ISSN 1547-0091, E-ISSN 2168-8028, Vol. 17, no 2, p. 333-343Article in journal (Refereed) Published
Abstract [en]
Hybrid sol–gel coatings are widely used as protective layers for aluminum alloys because of their barrier abilities. This study aims at explaining the barrier properties of a sol–gel coating based on alkyltrimethoxysilane and methacrylate resin by its film structure. This approach was examined by modifying one photopolymerization parameter, e.g., by varying the content of radical photoinitiator. By neutral salt spray test and electrochemical impedance spectroscopy, the barrier properties are highlighted. The film structure is related to thermomechanical properties of films whose glass transition temperature and elastic modulus are measured by dynamic mechanical analysis and nanoindentation, respectively. On a finer scale, conversion of methacrylate functions calculated from Fourier transform infrared spectroscopy has given information on the chemical structure of films. The morphology of these coatings is studied by scanning electron microscopy, transmission electron microscopy, atomic force microscopy operating in tapping mode, and X-ray diffraction. Results revealed that formulations containing between 3 and 9 wt% of radical photoinitiator exhibit the maximal conversion of methacrylate functions and, at a microscopic scale, a homogeneous coating where the two organic and inorganic networks are well interpenetrated. This hybrid sol–gel microstructure corresponds to the highest glass transition temperature and the highest mechanical characteristics (elastic modulus, E and hardness, H) and the highest protection performance. This results in the best barrier properties, and thus the highest corrosion resistance.
Place, publisher, year, edition, pages
Springer , 2020. Vol. 17, no 2, p. 333-343
Keywords [en]
Barrier, Hybrid sol–gel coatings, Nanostructure, Thermomechanics, Aluminum alloys, Atomic force microscopy, Corrosion resistance, Curing, Elastic moduli, Electrochemical corrosion, Electrochemical impedance spectroscopy, Glass, Glass transition, High resolution transmission electron microscopy, Morphology, Nanostructures, Photopolymerization, Scanning electron microscopy, Sols, Temperature, Fourier transform infra reds, Gel coatings, Mechanical characteristics, Neutral salt spray test, Photoinitiator contents, Thermo-mechanics, Thermomechanical properties, Aluminum coatings
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:ri:diva-50112DOI: 10.1007/s11998-019-00276-5Scopus ID: 2-s2.0-85074275157OAI: oai:DiVA.org:ri-50112DiVA, id: diva2:1497179
Note
Funding details: 2016/0726; Funding text 1: French National Association for Research and Technology (CIFRE Grant No. 2016/0726, research program MENHIRS) is gratefully acknowledged for financial support. The authors wish to thank A. Nazarov from French Corrosion Institute (Brest, France), who performed electrical impedance spectroscopy measurements. N. Gautier from IMN (UMR CNRS 6502, University of Nantes, France) is thanked for TEM analysis. We thank E. Balnois (LUBEM-Quimper, University Bretagne Occidentale) for AFM measurements and discussions. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
2020-11-042020-11-042023-05-26Bibliographically approved